Telematics system for vehicle diagnostics

ABSTRACT

Vehicle diagnostic system which diagnoses the state of the vehicle or the state of a component of the vehicle and generates an output indicative or representative thereof. A communications device transmits the output of the diagnostic system to a remote location, possibly via a satellite or the Internet. The diagnostic system can include sensors mounted on the vehicle, each providing a measurement related to a state of the sensor or a measurement related to a state of the mounting location, and a processor coupled to the sensors and arranged to receive data from the sensors and process the data to generate the output indicative or representative of the state of the vehicle or its component. The processor may embody a pattern recognition algorithm trained to generate the output from the data received from the sensors and be arranged to control parts of the vehicle based on the output.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/753,186 filed Jan. 2, 2001 which in turn is acontinuation-in-part of U.S. patent application Ser. No. 09/137,918filed Aug. 20, 1998, now U.S. Pat. No. 6,175,787, which in turn is acontinuation-in-part of U.S. patent application Ser. No. 08/476,077filed Jun. 7, 1995, now U.S. Pat. No. 5,809,437.

[0002] This application is a continuation-in-part of U.S. patentapplication Ser. No. 10/079,065 filed Feb. 19, 2002 which in turn is acontinuation-in-part of U.S. patent application Ser. No. 09/765,558filed Jan. 19, 2001, which claims priority under 35 U.S.C. § 119(e) ofU.S. provisional patent application Ser. No. 60/231,378 filed Sep. 8,2000.

[0003] This application claims priority under 35 U.S.C. § 119(e) of U.S.provisional patent application Ser. No. 60/269,415 filed Feb. 16, 2001,U.S. provisional patent application Ser. No. 60/291,511 filed May 16,2001 and U.S. provisional patent application Ser. No. 60/304,013 filedJul. 9, 2001 through U.S. patent application Ser. No. 10/079,065 filedFeb. 19, 2002.

[0004] This application is a continuation-in-part of U.S. patentapplication Ser. No. 10/174,709 filed Jun. 19, 2002.

[0005] All of the above-mentioned patents and applications areincorporated by reference herein in their entirety as if they had eachbeen set forth herein in full.

FIELD OF THE INVENTION

[0006] The present invention relates to methods and apparatus fordiagnosing components in a vehicle and transmitting data relating to thediagnosis of the components in the vehicle and other informationrelating to the operating conditions of the vehicle to one or moreremote locations distant from the vehicle, i.e., via a telematics link.

[0007] The present invention also relates to systems and method fordiagnosing the state or condition of a vehicle, e.g., whether thevehicle is about to rollover or is experiencing a crash and whether thevehicle has a component which is operating abnormally and could possiblyfail resulting in a crash or severe handicap for the operator, andtransmitting data relating to the diagnosis of the components in thevehicle and optionally other information relating to the operatingconditions of the vehicle to one or more remote locations, i.e., via atelematics link.

[0008] The present invention further relates to methods and apparatusfor diagnosing components in a vehicle and determining the status ofoccupants in a vehicle and transmitting data relating to the diagnosisof the components in the vehicle, and optionally other informationrelating to the operating conditions of the vehicle, and data relatingto the occupants to one or more remote facilities such as a repairfacility and an emergency response station.

BACKGROUND OF THE INVENTION

[0009] It is now generally recognized that it is important to monitorthe occupancy of a passenger compartment of a vehicle. For example, U.S.Pat. No. 5,829,782 (Breed et al.) describes a vehicle interiormonitoring system that utilizes pattern recognition techniques andwave-receiving sensors to obtain information about the occupancy of thepassenger compartment and uses this information to affect the operationof one or more systems in the vehicle, including an occupant restraintdevice, an entertainment system, a heating and air-conditioning system,a vehicle communication system, a distress notification system, a lightfiltering system and a security system.

[0010] Of particular interest, Breed et al. mentions that the presenceof a child in a rear facing child seat placed on the right frontpassenger seat may be detected as this has become an industry-wideconcern to prevent deployment of an occupant restraint device in thesesituations. The U.S. automobile industry is continually searching for aneasy, economical solution, which will prevent the deployment of thepassenger side airbag if a rear facing child seat is present.

[0011] Another important aspect disclosed in Breed et al. relates to theoperation of the cellular communications system in conjunction with thevehicle interior monitoring system. Vehicles can be provided with astandard cellular phone as well as the Global Positioning System (GPS),an automobile navigation or location system with an optional connectionto a manned assistance facility. In the event of an accident, the phonemay automatically call 911 for emergency assistance and report the exactposition of the vehicle. If the vehicle also has a system as describedbelow for monitoring each seat location, the number and perhaps thecondition of the occupants could also be reported. In that way, theemergency service (EMS) would know what equipment and how manyambulances to send to the accident site. Moreover, a communicationchannel can be opened between the vehicle and a monitoringfacility/emergency response facility or personnel to determine how badlypeople are injured, the number of occupants in the vehicle, and toenable directions to be provided to the occupant(s) of the vehicle toassist in any necessary first aid prior to arrival of the emergencyassistance personnel.

[0012] Communications between a vehicle and a remote assistance facilityare also important for the purpose of diagnosing problems with thevehicle and forecasting problems with the vehicle, called prognostics.Motor vehicles contain complex mechanical systems that are monitored andregulated by computer systems such as electronic control units (ECUs)and the like. Such ECUs monitor various components of the vehicleincluding engine performance, carburation, speed/acceleration control,transmission, exhaust gas recirculation (EGR), braking systems, etc.However, vehicles perform such monitoring typically only for the vehicledriver and without communication of any impending results, problemsand/or vehicle malfunction to a remote site for trouble-shooting,diagnosis or tracking for data mining.

[0013] In the past, systems that provide for remote monitoring did notprovide for automated analysis and communication of problems orpotential problems and recommendations to the driver. As a result, thevehicle driver or user is often left stranded, or irreparable damageoccurs to the vehicle as a result of neglect or driving the vehiclewithout the user knowing the vehicle is malfunctioning until it is toolate, such as low oil level and a malfunctioning warning light, fan beltabout to fail, failing radiator hose etc.

[0014] In this regard, U.S. Pat. No. 5,400,018 (Scholl et al.) describesa system for relaying raw sensor output from an off road work siterelating to the status of a vehicle to a remote location over acommunications data link. The information consists of fault codesgenerated by sensors and electronic control modules indicating that afailure has occurred rather than forecasting a failure. The vehicle doesnot include a system for performing diagnosis. Rather, the raw sensordata is processed at an off-vehicle location in order to arrive at adiagnosis of the vehicle's operating condition. Bi-directionalcommunications are described in that a request for additionalinformation can be sent to the vehicle from the remote location with thevehicle responding and providing the requested information but no suchcommunication takes place with the vehicle operator and not of anoperator of a vehicle traveling on a road. Also, Scholl et al. does notteach the diagnostics of the problem or potential problem on the vehicleitself nor does it teach the automatic diagnostics or any prognostics.In Scholl et al. the determination of the problem occurs at the remotesite by human technicians.

[0015] U.S. Pat. No. 5,754,965 (Hagenbuch) describes an apparatus fordiagnosing the state of health of a vehicle and providing the operatorof the vehicle with a substantially real-time indication of theefficiency of the vehicle in performing as assigned task with respect toa predetermined goal. A processor in the vehicle monitors sensors thatprovide information regarding the state of health of the vehicle and theamount of work the vehicle has done. The processor records informationthat describes events leading up to the occurrence of an anomaly forlater analysis. The sensors are also used to prompt the operator tooperate the vehicle at optimum efficiency.

[0016] U.S. Pat. No. 5,955,942 (Slifkin et al.) describes a method formonitoring events in vehicles in which electrical outputs representativeof events in the vehicle are produced, the characteristics of one eventare compared with the characteristics of other events accumulated over agiven period of time and departures or variations of a given extent fromthe other characteristics are determined as an indication of asignificant event. A warning is sent in response to the indication,including the position of the vehicle as determined by a globalpositioning system on the vehicle. For example, for use with a railroadcar, a microprocessor responds to outputs of an accelerometer bycomparing acceleration characteristics of one impact with accumulatedacceleration characteristics of other impacts and determines departuresof a given magnitude from the other characteristics as a failureindication which gives rise of a warning.

[0017] Every automobile driver fears that his or her vehicle willbreakdown at some unfortunate time, e.g., when he or she is traveling atnight, during rush hour, or on a long trip away from home. To helpalleviate that fear, certain luxury automobile manufacturers provideroadside service in the event of a breakdown. Nevertheless, unless thevehicle is equipped with OnStar® or an equivalent service, the vehicledriver must still be able to get to a telephone to call for service. Itis also a fact that many people purchase a new automobile out of fear ofa breakdown with their current vehicle. This invention is primarilyconcerned with preventing breakdowns and with minimizing maintenancecosts by predicting component failure that would lead to such abreakdown before it occurs.

[0018] When a vehicle component begins to fail, the repair cost isfrequently minimal if the impending failure of the component is caughtearly, but increases as the repair is delayed. Sometimes if a componentin need of repair is not caught in a timely manner, the component, andparticularly the impending failure thereof, can cause other componentsof the vehicle to deteriorate. One example is where the water pump failsgradually until the vehicle overheats and blows a head gasket. It isdesirable, therefore, to determine that a vehicle component is about tofail as early as possible so as to minimize the probability of abreakdown and the resulting repair costs.

[0019] There are various gages on an automobile which alert the driverto various vehicle problems. For example, if the oil pressure dropsbelow some predetermined level, the driver is warned to stop his vehicleimmediately. Similarly, if the coolant temperature exceeds somepredetermined value, the driver is also warned to take immediatecorrective action. In these cases, the warning often comes too late asmost vehicle gages alert the driver after he or she can convenientlysolve the problem. Thus, what is needed is a component failure warningsystem that alerts the driver to the impending failure of a componentsufficiently in advance of the time when the problem gets to acatastrophic point.

[0020] Some astute drivers can sense changes in the performance of theirvehicle and correctly diagnose that a problem with a component is aboutto occur. Other drivers can sense that their vehicle is performingdifferently but they don't know why or when a component will fail or howserious that failure will be, or possibly even what specific componentis the cause of the difference in performance. The invention disclosedherein will, in most cases, solve this problem by predicting componentfailures in time to permit maintenance and thus prevent vehiclebreakdowns.

[0021] Presently, automobile sensors in use are based on specificpredetermined or set levels, such as the coolant temperature or oilpressure, whereby an increase above the set level or a decrease belowthe set level will activate the sensor, rather than being based onchanges in this level over time. The rate at which coolant heats up, forexample, can be an important clue that some component in the coolingsystem is about to fail. There are no systems currently on automobilesto monitor the numerous vehicle components over time and to comparecomponent performance with normal performance. Nowhere in the vehicle isthe vibration signal of a normally operating front wheel stored, forexample, or for that matter, any normal signal from any other vehiclecomponent. Additionally, there is no system currently existing on avehicle to look for erratic behavior of a vehicle component and to warnthe driver or the dealer that a component is misbehaving and istherefore likely to fail in the very near future.

[0022] Sometimes, when a component fails, a catastrophic accidentresults. In the Firestone tire case, for example, over 100 people werekilled when a tire of a Ford Explorer blew out which caused the FordExplorer to rollover. Similarly, other component failures can lead toloss of control of the vehicle and a subsequent accident. It is thusvery important to accurately forecast that such an event will take placebut furthermore, for those cases where the event takes place suddenlywithout warning, it is also important to diagnose the state of theentire vehicle, which in some cases can lead to automatic correctiveaction to prevent unstable vehicle motion or rollovers resulting in anaccident. Finally, an accurate diagnostic system for the entire vehiclecan determine much more accurately the severity of an automobile crashonce it has begun by knowing where the accident is taking place on thevehicle (e.g., the part of or location on the vehicle which is beingimpacted by an object) and what is colliding with the vehicle based on aknowledge of the force deflection characteristics of the vehicle at thatlocation. Therefore, in addition to a component diagnostic, theteachings of this invention also provide a diagnostic system for theentire vehicle prior to and during accidents. In particular, thisinvention is concerned with the simultaneous monitoring of multiplesensors on the vehicle so that the best possible determination of thestate of the vehicle can be determined. Current crash sensors operateindependently or at most one sensor may influence the threshold at whichanother sensor triggers a deployable restraint. In the teachings of thisinvention, two or more sensors, frequently accelerometers, are monitoredsimultaneously and the combination of the outputs of these multiplesensors are combined continuously in making the crash severity analysis.

[0023] Marko et al. (U.S. Pat. No. 5,041,976) is directed to adiagnostic system using pattern recognition for electronic automotivecontrol systems and particularly for diagnosing faults in the engine ofa motor vehicle after they have occurred. For example, Marko et al. isinterested in determining cylinder specific faults after the cylinder isoperating abnormally. More specifically, Marko et al. is directed todetecting a fault in a vehicular electromechanical system indirectly,i.e., by means of the measurement of parameters of sensors which areaffected by that system, and after that fault has already manifesteditself in the system. In order to form the fault detecting system, theparameters from these sensors are input to a pattern recognition systemfor training thereof Then known faults are introduced and the parametersfrom the sensors are inputted into the pattern recognition system withan indicia of the known fault. Thus, during subsequent operation, thepattern recognition system can determine the fault of theelectromechanical system based on the parameters of the sensors,assuming that the fault was “trained” into the pattern recognitionsystem and has already occurred.

[0024] When the electromechanical system is an engine, the parametersinput into the pattern recognition system for training thereof, and usedfor fault detection during operation, all relate to the engine. (If theelectromechanical system is other than the engine, then the parametersinput into the pattern recognition system would relate to that system.)In other words, each parameter will be affected by the operation of theengine and depend thereon and changes in the operation of the enginewill alter the parameter, e.g., the manifold absolute pressure is anindication of the airflow into the engine. In this case, the signal fromthe manifold absolute pressure sensor may be indicative of a fault inthe intake of air into the engine, e.g., the engine is drawing in toomuch or too little air, and is thus affected by the operation of theengine. Similarly, the mass air flow is the airflow into the engine andis an alternative to the manifold absolute pressure. It is thus aparameter that is directly associated with, related to and dependent onthe engine. The exhaust gas oxygen sensor is also affected by theoperation of the engine, and thus directly associated therewith, sinceduring normal operation, the mixture of the exhaust gas is neither richor lean whereas during abnormal engine operation, the sensor will detectan abrupt change indicative of the mixture being too rich or too lean.

[0025] Thus, the system of Marko et al. is based on the measurement ofsensors which affect or are affected by, i.e., are directly associatedwith, the operation of the electromechanical system for which faults areto be detected. However, the system of Marko et al. does not detectfaults in the sensors that are conducting the measurements, e.g., afault in the exhaust gas oxygen sensor, or faults that are onlydeveloping but have not yet manifested themselves or faults in othersystems. Rather, the sensors are used to detect a fault in the systemafter it has occurred.

[0026] Asami et al. (U.S. Pat. No. 4,817,418) is directed to a failurediagnosis system for a vehicle including a failure display means fordisplaying failure information to a driver. This system only reportsfailures after they have occurred and does not predict them.

[0027] Tiernan et al. (U.S. Pat. No. 5,313,407) is directed, inter alia,to a system for providing an exhaust active noise control system, i.e.,an electronic muffler system, including an input microphone 60 whichsenses exhaust noise at a first location 61 in an exhaust duct 58. Anengine has exhaust manifolds 56,57 feeding exhaust air to the exhaustduct 58. The exhaust noise sensed by the microphone 60 is processed toobtain an output from an output speaker 65 arranged downstream of theinput microphone 61 in the exhaust path in order to cancel the noise inthe exhaust duct 58.

[0028] Haramaty et al. (U.S. Pat. No. 5,406,502) describes a system thatmonitors a machine in a factory and notifies maintenance personnelremote from the machine (not the machine operator) that maintenanceshould be scheduled at a time when the machine is not in use. Haramatyet al. does not expressly relate to vehicular applications.

[0029] NASA Technical Support Package MFS-26529 “Engine Monitoring Basedon Normalized Vibration Spectra”, describes a technique for diagnosingengine health using a neural network based system and is incorporated byreference herein in its entirety.

[0030] A paper “Using acoustic emission signals for monitoring ofproduction processes” by H. K. Tonshoff et al. also provides a gooddescription of how acoustic signals can be used to predict the state ofmachine tools and is incorporated by reference herein in its entirety.

[0031] Based on the monitoring of vehicular components, systems andsubsystems as well as to the measurement of physical and chemicalcharacteristics relating to the vehicle or its components, systems andsubsystems, it becomes possible to control and/or affect one or morevehicular system.

[0032] An important component or system which is monitored is the tiresas failure of one or more of the tires can often lead to a fatalaccident. Indeed, tire monitoring is extremely important since NHTSA(National Highway Traffic Safety Administration) has recently linked 148deaths and more than 525 injuries in the United States to separations,blowouts and other tread problems in Firestone's ATX, ATX II andWilderness AT tires, 5 million of which were recalled in 2000. Many ofthe tires were standard equipment on the Ford Explorer. Ford recommendsthat the Firestone tires on the Explorer sport utility vehicle beinflated to 26 psi, while Firestone recommends 30 psi. It is surprisingthat a tire can go from a safe condition to an unsafe condition based onan under inflation of 4 psi.

[0033] Recent studies in the United States conducted by the Society ofAutomotive Engineers show that low tire pressure causes about 260,000accidents annually. Another finding is that about 75% of tire failureseach year are preceded by slow air leaks or inadequate tire inflation.Nissan, for example, warns that incorrect tire pressures can compromisethe stability and overall handling of a vehicle and can contribute to anaccident. Additionally, most non-crash auto fatalities occur whiledrivers are changing flat tires. Thus, tire failures are clearly aserious automobile safety problem that requires a solution.

[0034] About 16% of all car accidents are a result of incorrect tirepressure. Thus, effective pressure and wear monitoring is extremelyimportant. Motor Trend magazine stated that one of the most overlookedmaintenance areas on a car is tire pressure. An estimated 40 to 80percent of all vehicles on the road are operating with under-inflatedtires. When under-inflated, a tire tends to flex its sidewall more,increasing its rolling resistance which decreases fuel economy. Theextra flex also creates excessive heat in the tire that can shorten itsservice life.

[0035] The Society of Automotive Engineers reports that about 87 percentof all flat tires have a history of under-inflation. About 85% ofpressure loss incidents are slow punctures caused either bysmall-diameter objects trapped in the tire or by larger diameter nails.The leak will be minor as long as the nail is trapped. If the nail comesout, pressure can decrease rapidly. Incidents of sudden pressure lossare potentially the most dangerous for drivers and account for about 15%of all cases.

[0036] A properly inflated tire loses approximately 1 psi per month. Adefective time can lose pressure at a more rapid rate. About 35 percentof the recalled Bridgestone tires had improper repairs.

[0037] Research from a variety of sources suggests that under-inflationcan be significant to both fuel economy and tire life. Industry expertshave determined that tires under-inflated by a mere 10% wear out about15% faster. An average driver with an average set of tires can drive anextra 5,000 to 7,000 miles before buying new tires by keeping the tireproperly inflated.

[0038] The American Automobile Association has determined that underinflated tires cut a vehicle's fuel economy by as much as 2% per psibelow the recommended level. If each of a car's tires is supposed tohave a pressure of 30 psi and instead has a pressure of 25 psi, thecar's fuel efficiency drops by about 10%. Depending on the vehicle andmiles driven that could cost from $100 to $500 a year.

[0039] The ability to control a vehicle is strongly influenced by tirepressure. When the tire pressure is kept at proper levels, optimumvehicle braking, steering, handling and stability are accomplished. Lowtire pressure can also lead to damage to both the tires and wheels.

[0040] A Michelin study revealed that the average driver doesn'trecognize a low tire until it's 14 psi too low. One of the reasons isthat today's radial tire is hard to judge visually because the sidewallflexes even when properly inflated.

[0041] Despite all the recent press about keeping tires properlyinflated, new research shows that most drivers do not know the correctinflation pressure. In a recent survey, only 45 percent of respondentsknew where to look to find the correct pressure, even though 78 percentthought they knew. Twenty-seven percent incorrectly believed thesidewall of the tire carries the correct information and did not knowthat the sidewall only indicates the maximum pressure for the tire, notthe optimum pressure for the vehicle. In another survey, about 60% ofthe respondents reported that they check tire pressure but only beforegoing on a long trip. The National Highway Traffic Safety Administrationestimates that at least one out of every five tires is not properlyinflated.

[0042] The problem is exacerbated with the new run-flat tires where adriver may not be aware that a tire is flat until it is destroyed.Run-flat tires can be operated at air pressures below normal for alimited distance and at a restricted speed (125 miles at a maximum of 55mph). The driver must therefore be warned of changes in the condition ofthe tires so that she can adapt her driving to the changed conditions.

[0043] One solution to this problem is to continuously monitor thepressure and perhaps the temperature in the tire. Pressure loss can beautomatically detected in two ways: by directly measuring air pressurewithin the tire or by indirect tire rotation methods. Various indirectmethods are based on the number of revolutions each tire makes over anextended period of time through the ABS system and others are based onmonitoring the frequency changes in the sound emitted by the tire. Inthe direct detection case, a sensor is mounted into each wheel or tireassembly, each with its own identity. An on-board computer collects thesignals, processes and displays the data and triggers a warning signalin the case of pressure loss.

[0044] Under-inflation isn't the only cause of sudden tire failure. Avariety of mechanical problems including a bad wheel bearing or a“dragging” brake can cause the tire to heat up and fail. In addition, asmay have been a contributing factor in the Firestone case, substandardmaterials can lead to intra-tire friction and a buildup of heat. The useof re-capped truck tires is another example of heat caused failure as aresult by intra-tire friction. An overheated tire can fail suddenlywithout warning.

[0045] As discussed in more detail below, tire monitors, such as thosedisclosed below, permit the driver to check the vehicle tire pressuresfrom inside the vehicle.

[0046] The Transportation Recall Enhancement Accountability andDocumentation Act, (H.R. 5164, or Public Law No. 106-414) known as theTREAD Act, was signed by President Clinton on Nov. 1, 2000. Section 12,TIRE PRESSURE WARNING, states that: “Not later than one year after thedate of enactment of this Act, the Secretary of Transportation, actingthrough the National Highway Traffic Safety Administration, shallcomplete a rulemaking for a regulation to require a warning system in amotor vehicle to indicate to the operator when a tire is significantlyunder-inflated. Such requirement shall become effective not later than 2years after the date of the completion of such rulemaking.” Thus, it isexpected that a rule requiring continuous tire monitoring will takeeffect for the 2004 model year.

[0047] This law will dominate the first generation of such systems asautomobile manufacturers move to satisfy the requirement. In subsequentyears, more sophisticated systems that in addition to pressure willmonitor temperature, tire footprint, wear, vibration, etc. Although theAct requires that the tire pressure be monitored, it is believed by theinventors that other parameters are as important as the tire pressure oreven more important than the tire pressure as described in more detailbelow.

[0048] Consumers are also in favor of tire monitors. Johnson Controls'market research showed that about 80 percent of consumers believe a lowtire pressure warning system is an important or extremely importantvehicle feature. Thus, as with other safety products such as airbags,competition to meet customer demands will soon drive this market.

[0049] Although, as with most other safety products, the initialintroductions will be in the United States, speed limits in the UnitedStates and Canada are sufficiently low that tire pressure is not ascritical an issue as in Europe, for example, where the drivers oftendrive much faster.

[0050] The advent of microelectromechanical (MEMS) pressure sensors,especially those based on surface acoustical wave (SAW) technology, hasnow made the wireless and powerless monitoring of tire pressurefeasible. This is the basis of the tire pressure monitors describedbelow. According to a Frost and Sullivan report on the U.S.Micromechanical Systems (MEMS) market (June 1997): “A MEMS tire pressuresensor represents one of the most profound opportunities for MEMS in theautomotive sector.”

[0051] There are many wireless tire temperature and pressure monitoringsystems disclosed in the prior art patents such as for example, U.S.Pat. Nos. 4,295,102, 4,296,347, 4,317,372, 4,534,223, 5,289,160,5,612,671, 5,661,651, 5,853,020 and 5,987,980 and InternationalPublication No. WO 01/07271(A1), all of which are illustrative of thestate of the art of tire monitoring and are incorporated by referenceherein.

[0052] Devices for measuring the pressure and/or temperature within avehicle tire directly can be categorized as those containing electroniccircuits and a power supply within the tire, those which containelectronic circuits and derive the power to operate these circuitseither inductively, from a generator or through radio frequencyradiation, and those that do not contain electronic circuits and receivetheir operating power only from received radio frequency radiation. Forthe reasons discussed above, the discussion herein is mainly concernedwith the latter category. This category contains devices that operate onthe principles of surface acoustic waves (SAW) and the disclosure belowis concerned primarily with such SAW devices.

[0053] International Publication No. WO 01/07271 describes a tirepressure sensor that replaces the valve and valve stem in a tire.

[0054] U.S. Pat. No. 5,231,827 contains a good description andbackground of the tire-monitoring problem. The device disclosed,however, contains a battery and electronics and is not a SAW device.Similarly, the device described in U.S. Pat. No. 5,285,189 contains abattery as do the devices described in U.S. Pat. Nos. 5,335,540 and5,559,484. U.S. Pat. No. 5,945,908 applies to a stationary tiremonitoring system and does not use SAW devices.

[0055] One of the first significant SAW sensor patents is U.S. Pat. No.4,534,223. This patent describes the use of SAW devices for measuringpressure and also a variety of methods for temperature compensation butdoes not mention wireless transmission.

[0056] U.S. Pat. No. 5,987,980 describes a tire valve assembly using aSAW pressure transducer in conjunction with a sealed cavity. This patentdoes disclose wireless transmission. The assembly includes a powersupply and thus this also distinguishes it from a preferred system ofthis invention. It is not a SAW system and thus the antenna forinterrogating the device in this design must be within one meter, whichis closer than needed for a preferred device of this invention.

[0057] U.S. Pat. No. 5,698,786 relates to the sensors and is primarilyconcerned with the design of electronic circuits in an interrogator.U.S. Pat. No. 5,700,952 also describes circuitry for use in theinterrogator to be used with SAW devices. In neither of these patents isthe concept of using a SAW device in a wireless tire pressure monitoringsystem described. These patents also do not describe including anidentification code with the temperature and/or pressure measurements inthe sensors and devices.

[0058] U.S. Pat. No. 5,804,729 describes circuitry for use with aninterrogator in order to obtain more precise measurements of the changesin the delay caused by the physical or chemical property being measuredby the SAW device. Similar comments apply to U.S. Pat. No. 5,831,167.Other related prior art includes U.S. Pat. No. 4,895,017.

[0059] Other patents disclose the placement of an electronic device inthe sidewall or opposite the tread of a tire but they do not discloseeither an accelerometer or a surface acoustic wave device. In mostcases, the disclosed system has a battery and electronic circuits.

[0060] One method of measuring pressure that is applicable to thisinvention is disclosed in V. V. Varadan, Y. R. Roh and V. K. Varadan“Local/Global SAW Sensors for Turbulence”, IEEE 1989 UltrasonicsSymposium p. 591-594 makes use of a polyvinylidene fluoride (PVDF)piezoelectric film to measure pressure. Mention is made in this articlethat other piezoelectric materials can also be used. Experimentalresults are given where the height of a column of oil is measured basedon the pressure measured by the piezoelectric film used as a SAW device.In particular, the speed of the surface acoustic wave is determined bythe pressure exerted by the oil on the SAW device. For the purposes ofthe instant invention, air pressure can also be measured in a similarmanner by first placing a thin layer of a rubber material onto thesurface of the SAW device which serves as a coupling agent from the airpressure to the SAW surface. In this manner, the absolute pressure of atire, for example, can be measured without the need for a diaphragm andreference pressure greatly simplifying the pressure measurement. Otherexamples of the use of PVDF film as a pressure transducer can be foundin U.S. Pat. Nos. 4,577,510 and 5,341,687, which are incorporated byreference herein, although they are not used as SAW devices.

[0061] The following U.S. patents provide relevant information to thisinvention, and to the extent necessary, all of them are incorporated byreference herein: U.S. Pat. Nos. 4,361,026, 4,620,191, 4,7033,27,4,724,443, 4,725,841, 4,734,698, 5,691,698, 5,841,214, 6,060,815,6,107,910, 6,114,971, 6,144,332.

[0062] In recent years, SAW devices have been used as sensors in a broadvariety of applications. Compared with sensors utilizing alternativetechnologies, SAW sensors possess outstanding properties, such as highsensitivity, high resolution, and ease of manufacturing bymicroelectronic technologies. However, the most attractive feature ofSAW sensors is that they can be interrogated wirelessly.

DEFINITIONS

[0063] As used herein, a diagnosis of the “state of the vehicle” means adiagnosis of the condition of the vehicle with respect to its stabilityand proper running and operating condition. Thus, the state of thevehicle could be normal when the vehicle is operating properly on ahighway or abnormal when, for example, the vehicle is experiencingexcessive angular inclination (e.g., two wheels are off the ground andthe vehicle is about to rollover), the vehicle is experiencing a crash,the vehicle is skidding, and other similar situations. A diagnosis ofthe state of the vehicle could also be an indication that one of theparts of the vehicle, e.g., a component, system or subsystem, isoperating abnormally.

[0064] As used herein, an “occupant restraint device” includes any typeof device which is deployable in the event of a crash involving thevehicle for the purpose of protecting an occupant from the effects ofthe crash and/or minimizing the potential injury to the occupant.Occupant restraint devices thus include frontal airbags, side airbags,seatbelt tensioners, knee bolsters, side curtain airbags, externallydeployable airbags and the like.

[0065] As used herein, a “part” of the vehicle includes any component,sensor, system or subsystem of the vehicle such as the steering system,braking system, throttle system, navigation system, airbag system,seatbelt retractor, air bag inflation valve, air bag inflationcontroller and airbag vent valve, as well as those listed below in thedefinitions of “component” and “sensor”.

[0066] As used herein, a “sensor system” includes any of the sensorslisted below in the definition of “sensor” as well as any type ofcomponent or assembly of components which detect, sense or measuresomething.

[0067] The term “gage” as used herein interchangeably with the terms“sensor” and “sensing device”.

[0068] Preferred embodiments of the invention are described below andunless specifically noted, it is the applicants' intention that thewords and phrases in the specification and claims be given the ordinaryand accustomed meaning to those of ordinary skill in the applicableart(s). If the applicant intends any other meaning, he will specificallystate he is applying a special meaning to a word or phrase.

[0069] Likewise, applicants' use of the word “function” here is notintended to indicate that the applicants seek to invoke the specialprovisions of 35 U.S.C. § 112, sixth paragraph, to define theirinvention. To the contrary, if applicants wish to invoke the provisionsof 35 U.S.C. § 112, sixth paragraph, to define their invention, theywill specifically set forth in the claims the phrases “means for” or“step for” and a function, without also reciting in that phrase anystructure, material or act in support of the function. Moreover, even ifapplicants invoke the provisions of 35 U.S.C. § 112, sixth paragraph, todefine their invention, it is the applicants' intention that theirinventions not be limited to the specific structure, material or actsthat are described in the preferred embodiments herein. Rather, ifapplicants claim their inventions by specifically invoking theprovisions of 35 U.S.C. § 112, sixth paragraph, it is nonetheless theirintention to cover and include any and all structure, materials or actsthat perform the claimed function, along with any and all known or laterdeveloped equivalent structures, materials or acts for performing theclaimed function.

OBJECTS OF THE INVENTION

[0070] It is an object of the present invention to provide a new andimproved method and system for diagnosing components in a vehicle andthe operating status of the vehicle and alerting the vehicle's dealer,or another repair facility, via a telematics link that a component ofthe vehicle is functioning abnormally and may be in danger of failing.

[0071] It is still another object of the present invention to provide anew and improved method and apparatus for obtaining information about avehicle system and components in the vehicle in conjunction with failureof the component or the vehicle and sending this information to thevehicle manufacturer.

[0072] It is an object of the present invention to provide a new andimproved method and system for diagnosing components in a vehicle bymonitoring the patterns of signals emitted from the vehicle componentsand, through the use of pattern recognition technology, forecastingcomponent failures before they occur. Vehicle component behavior is thusmonitored over time in contrast to systems that wait until a seriouscondition occurs. The forecast of component failure can be transmittedto a remote location via a telematics link.

[0073] It is another object of the present invention to provide a newand improved on-board vehicle diagnostic module utilizing patternrecognition technologies which are trained to differentiate normal fromabnormal component behavior. The diagnosis of component behavior can betransmitted to a remote location via a telematics link.

[0074] It is yet another object of the present invention to provide adiagnostic module that determines whether a component is operatingnormally or abnormally based on a time series of data from a singlesensor or from multiple sensors that contain a pattern indicative of theoperating status of the component. The diagnosis of component operationcan be transmitted to a remote location via a telematics link.

[0075] It is still another object of the present invention to provide adiagnostic module that determines whether a component is operatingnormally or abnormally based on data from one or more sensors that arenot directly associated with the component, i.e., do not depend on theoperation of the component. The diagnosis of component operation can betransmitted to a remote location via a telematics link.

[0076] It is an additional object of the present invention tosimultaneously monitor several sensors, primarily accelerometers,gyroscopes and strain gages, to determine the state of the vehicle andoptionally its occupants and to determine that a vehicle is out ofcontrol and possibly headed for an accident, for example. If so, then asignal can be sent to a part of the vehicle control system to attempt tore-establish stability. If this is unsuccessful, then the same system ofsensors can monitor the early stages of a crash to make an assessment ofthe severity of the crash and what occupant protection systems should bedeployed and how such occupant protection systems should be deployed.

[0077] Another object of the invention to provide new and improvedsensors for a vehicle which wirelessly transmits information about astate measured or detected by the sensor.

[0078] It is another object of the invention to incorporate surfaceacoustic wave technology into sensors on a vehicle with the dataobtained by the sensors being transmittable via a telematics link to aremote location.

[0079] It is another object of the invention to provide new and improvedsensors for measuring the pressure, temperature and/or acceleration oftires with the data obtained by the sensors being transmittable via atelematics link to a remote location.

[0080] It is yet another object of the invention to provide new andimproved weight or load measuring sensors, switches, temperaturesensors, acceleration sensors, angular position sensors, angular ratesensors, angular acceleration sensors, proximity sensors, rolloversensors, occupant presence and position sensors, strain sensors andhumidity sensors which utilize wireless data transmission, wirelesspower transmission, and/or surface acoustic wave technology with thedata obtained by the sensors being transmittable via a telematics linkto a remote location.

[0081] It is still another object of the present invention to providenew and improved sensors for detecting the presence of fluids or gaseswhich utilize wireless data transmission, wireless power transmission,and/or surface acoustic wave technology with the data obtained by thesensors being transmittable via a telematics link to a remote location.

[0082] Yet another object of the present invention to provide new andimproved sensors for detecting the condition or friction of a roadsurface which utilize wireless data transmission, wireless powertransmission, and/or surface acoustic wave technology with the dataobtained by the sensors being transmittable via a telematics link to aremote location.

[0083] Still another object of the present invention to provide new andimproved sensors for detecting chemicals which utilize wireless datatransmission, wireless power transmission, and/or surface acoustic wavetechnology with the data obtained by the sensors being transmittable viaa telematics link to a remote location.

[0084] It is another object of the invention to utilize any of theforegoing sensors for a vehicular component control system in which acomponent, system or subsystem in the vehicle is controlled based on theinformation provided by the sensor. Additionally, the informationprovided by the sensor can be transmitted via a telematics link to oneor more remote facilities for further analysis.

[0085] A more general object of the invention is to provide new andimproved sensors which obtain and provide information about the vehicle,about individual components, systems, vehicle occupants, subsystems, orabout the roadway, ambient atmosphere, travel conditions and externalobjects with the data obtained by the sensors being transmittable via atelematics link to a remote location.

[0086] Accordingly to achieve one or more of the above objects, avehicle in accordance with the invention comprises a diagnostic systemarranged to diagnose the state of the vehicle or the state of acomponent of the vehicle and generate an output indicative orrepresentative thereof and a communications device coupled to thediagnostic system and arranged to transmit the output of the diagnosticsystem. The diagnostic system may comprise a plurality of vehiclesensors mounted on the vehicle, each sensor providing a measurementrelated to a state of the sensor or a measurement related to a state ofthe mounting location, and a processor coupled to the sensors andarranged to receive data from the sensors and process the data togenerate the output indicative or representative of the state of thevehicle or the state of a component of the vehicle. The sensors may bewirelessly coupled to the processor and arranged at different locationson the vehicle. The processor may embody a pattern recognition algorithmtrained to generate the output from the data received from the sensors,such as a neural network, fuzzy logic, sensor fusion and the like, andbe arranged to control one or more parts of the vehicle based on theoutput indicative or representative of the state of the vehicle or thestate of a component of the vehicle. The state of the vehicle caninclude angular motion of the vehicle.

[0087] A display may be arranged in the vehicle in a position to bevisible from the passenger compartment. Such as display is coupled tothe diagnostic system and arranged to display the diagnosis of the stateof the vehicle or the state of a component of the vehicle.

[0088] A warning device may also be coupled to the diagnostic system forrelaying a warning to an occupant of the vehicle relating to the stateof the vehicle or the state of the component of the vehicle as diagnosedby the diagnostic system.

[0089] The communications device may comprise a cellular telephonesystem including an antenna as well as other similar or differentelectronic equipment capable of transmitting a signal to a remotelocation, optionally via a satellite. Transmission via the Internet,i.e., to a web site or host computer associated with the remote locationis also a possibility for the invention. If the vehicle is considered itsown site, then the transmission would be a site-to-site transmissionvia the Internet.

[0090] An occupant sensing system can be provided to determine at leastone property or characteristic of occupancy of the vehicle. In thiscase, the communications device is coupled to the occupant sensingsystem and transmits the determined property or characteristic ofoccupancy of the vehicle.

[0091] In a similar manner, at least one environment sensor can beprovided, each sensing a state of the environment around the vehicle. Inthis case, the communications device is coupled to the environmentsensor(s) and transmits the sensed state of the environment around thevehicle.

[0092] Moreover, a location determining system, optionally incorporatingGPS technology, could be provided on the vehicle to determine thelocation of the vehicle and transmitted to the remote location alongwith the diagnosis of the state of the vehicle or its component.

[0093] A memory unit may be coupled to the diagnostic system and thecommunications device. The memory unit receives the diagnosis of thestate of the vehicle or the state of a component of the vehicle from thediagnostic system and stores the diagnosis. The communications devicethen interrogates the memory unit to obtain the stored diagnosis toenable transmission thereof, e.g., at periodic intervals.

[0094] The sensors may be any known type of sensor including, but notlimited to, a single axis acceleration sensor, a double axisacceleration sensor, a triaxial acceleration sensor and a gyroscope. Thesensors may include an RFID response unit and an RFID interrogatordevice which causes the RFID response units to transmit a signalrepresentative of the measurement of the associated sensor to theprocessor. In addition to or instead or an RFID-based system, one ormore SAW sensors can be arranged on the vehicle, each receiving a signaland returning a signal modified by virtue of the state of the sensor orthe state of the mounting location of the sensor. For example, the SAWsensor can measure temperature and/or pressure of a component of thevehicle or in a certain location or space on the vehicle, or theconcentration and/or presence of a chemical

[0095] A method for monitoring a vehicle comprises diagnosing the stateof the vehicle or the state of a component of the vehicle by means of adiagnostic system arranged on the vehicle, generating an outputindicative or representative of the diagnosed state of the vehicle orthe diagnosed state of the component of the vehicle, and transmittingthe output to a remote location. Transmission of the output to a remotelocation may entail arranging a communications device comprising acellular telephone system including an antenna on the vehicle. Theoutput may be to a satellite for transmission from the satellite to theremote location. The output could also be transmitted via the Internetto a web site or host computer associated with the remote location.

[0096] It is important to note that raw sensor data is not transmittedfrom the vehicle the remote location for analysis and processing by thedevices and/or personnel at the remote location. Rather, in accordancewith the invention, a diagnosis of the vehicle or the vehicle componentis performed on the vehicle itself and this resultant diagnosis istransmitted.

[0097] The diagnosis of the state of the vehicle may encompassdetermining whether the vehicle is stable or is about to rollover orskid and/or determining a location of an impact between the vehicle andanother object.

[0098] A display may be arranged in the vehicle in a position to bevisible from the passenger compartment in which case, the state of thevehicle or the state of a component of the vehicle is displayed thereon.Further, a warning can be relayed to an occupant of the vehicle relatingto the state of the vehicle.

[0099] In addition to the transmission of vehicle diagnostic informationobtained by analysis of data from sensors performed on the vehicle, atleast one property or characteristic of occupancy of the vehicle may bedetermined (such as the number of occupants, the status of theoccupants-breathing or not, injured or not, etc.) and transmitted to aremote location, the same or a different remote location to which thediagnostic information is sent. The information can also be sent in adifferent manner than the information relating to the diagnosis of thevehicle.

[0100] Additional information for transmission by the components on thevehicle may include a state of the environment around the vehicle, forexample, the temperature, pressure, humidity, etc. in the vicinity ofthe vehicle, and the location of the vehicle.

[0101] A memory unit may be provided in the vehicle, possibly as part ofa microprocessor, and arranged to receive the diagnosis of the state ofthe vehicle or the state of the component of the vehicle and store thediagnosis. As such, this memory unit can be periodically interrogated toobtain the stored diagnosis to enable transmission thereof.

[0102] Diagnosis of the state of the vehicle or the state of thecomponent of the vehicle may entail mounting a plurality of sensors onthe vehicle, measuring a state of each sensor or a state of the mountinglocation of each sensor and diagnosing the state of the vehicle or thestate of a component of the vehicle based on the measurements of thestate of the sensors or the state of the mounting locations of thesensors. These functions can be achieved by a processor which iswirelessly coupled to the sensors.

[0103] The sensors can optionally be provided with RFID technology,i.e., an RFID response unit, whereby an RFID interrogator device ismounted on the vehicle and signals transmitted via the RFID interrogatordevice causes the RFID response units of any properly equipped sensorsto transmit a signal representative of the measurements of that sensorto the processor.

[0104] SAW sensors can also be used, in addition to or instead ofRFID-based sensors.

[0105] One embodiment of the diagnostic module in accordance with theinvention utilizes information which already exists in signals emanatingfrom various vehicle components along with sensors which sense thesesignals and, using pattern recognition techniques, compares thesesignals with patterns characteristic of normal and abnormal componentperformance to predict component failure, vehicle instability or a crashearlier than would otherwise occur if the diagnostic module was notutilized. If fully implemented, this invention is a total diagnosticsystem of the vehicle. In most implementations, the module is attachedto the vehicle and electrically connected to the vehicle data bus whereit analyzes data appearing on the bus to diagnose components of thevehicle. In some implementations, multiple distributed accelerometersand/or microphones are present on the vehicle and, in some cases, someof the sensors will communicate using wireless technology to the vehiclebus or directly to the diagnostic module.

[0106] Principal objects and advantages of this invention or otherinventions disclosed herein are thus:

[0107] 1. To prevent vehicle breakdowns.

[0108] 2. To alert the driver of the vehicle that a component of thevehicle is functioning differently than normal and might be in danger offailing.

[0109] 3 To alert the dealer, or other repair facility, that a componentof the vehicle is functioning differently than normal and is in dangerof failing.

[0110] 4. To provide an early warning of a potential component failureand to thereby minimize the cost of repairing or replacing thecomponent.

[0111] 5. To provide a device which will capture available informationfrom signals emanating from vehicle components for a variety of usessuch as current and future vehicle diagnostic purposes.

[0112] 6. To provide a device that uses information from existingsensors for new purposes thereby increasing the value of existingsensors and, in some cases, eliminating the need for sensors thatprovide redundant information.

[0113] 7. To provide a device which is trained to recognizedeterioration in the performance of a vehicle component, or of theentire vehicle, based on information in signals emanating from thecomponent or from vehicle angular and linear accelerations.

[0114] 8. To provide a device which analyzes vibrations from variousvehicle components that are transmitted through the vehicle structureand sensed by existing vibration sensors such as vehicular crash sensorsused with airbag systems or by special vibration sensors,accelerometers, or gyroscopes.

[0115] 9. To provide a device which provides information to the vehiclemanufacturer of the events leading to a component failure.

[0116] 10. To apply pattern recognition techniques based on training todiagnosing potential vehicle component failures.

[0117] 11. To apply component diagnostic techniques in combination withintelligent or smart highways wherein vehicles may be automaticallyguided without manual control in order to permit the orderly exiting ofthe vehicle from a restricted roadway prior to a breakdown of thevehicle.

[0118] 12. To apply trained pattern recognition techniques usingmultiple sensors to provide an early prediction of the existence andseverity of an accident.

[0119] 13. To utilize pattern recognition techniques and the output frommultiple sensors to determine at an early stage that a vehicle rollovermight occur and to take corrective action through control of the vehicleacceleration, brakes and steering to prevent the rollover or if it ispreventable, to deploy side head protection airbags to reduce theinjuries.

[0120] 14. To use the output from multiple sensors to determine that thevehicle is skidding or sliding and to send messages to the variousvehicle control systems to activate the throttle, brakes and/or steeringto correct for the vehicle sliding or skidding motion.

[0121] Other objects and advantages of the present invention will becomeapparent from the following description of the preferred embodimentstaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0122] The following drawings are illustrative of embodiments of thesystem developed or adapted using the teachings of this invention andare not meant to limit the scope of the invention as encompassed by theclaims.

[0123]FIG. 1 is a side view with parts cutaway and removed of a vehicleshowing the passenger compartment containing a rear facing child seat onthe front passenger seat and a preferred mounting location for anoccupant and rear facing child seat presence detector.

[0124]FIG. 2 is a side view with parts cutaway and removed showingschematically the interface between the vehicle interior monitoringsystem of this invention and the vehicle cellular communication system.

[0125]FIG. 3 is a diagram of one exemplifying embodiment of theinvention.

[0126]FIG. 4 is a perspective view of a carbon dioxide SAW sensor formounting in the trunk lid for monitoring the inside of the trunk fordetecting trapped children or animals.

[0127]FIG. 4A is a detailed view of the SAW carbon dioxide sensor ofFIG. 4.

[0128]FIG. 5 is a schematic illustration of a generalized component withseveral signals being emitted and transmitted along a variety of paths,sensed by a variety of sensors and analyzed by the diagnostic module inaccordance with the invention and for use in a method in accordance withthe invention.

[0129]FIG. 6 is a schematic of one pattern recognition methodology knownas a neural network which may be used in a method in accordance with theinvention.

[0130]FIG. 7 is a schematic of a vehicle with several components andseveral sensors and a total vehicle diagnostic system in accordance withthe invention utilizing a diagnostic module in accordance with theinvention and which may be used in a method in accordance with theinvention.

[0131]FIG. 8 is a flow diagram of information flowing from varioussensors onto the vehicle data bus and thereby into the diagnostic modulein accordance with the invention with outputs to a display for notifyingthe driver, and to the vehicle cellular phone for notifying anotherperson, of a potential component failure.

[0132]FIG. 9 is a flow chart of the methods for automatically monitoringa vehicular component in accordance with the invention.

[0133]FIG. 10 is a schematic illustration of the components used in themethods for automatically monitoring a vehicular component.

[0134]FIG. 11 is a schematic of a vehicle with several accelerometersand/or gyroscopes at preferred locations in the vehicle.

[0135]FIG. 12 is a schematic view of overall telematics system inaccordance with the invention.

[0136]FIG. 13A is a partial cutaway view of a tire pressure monitorusing an absolute pressure measuring SAW device.

[0137]FIG. 13B is a partial cutaway view of a tire pressure monitorusing a differential pressure measuring SAW device.

[0138]FIG. 14 is a partial cutaway view of an interior SAW tiretemperature and pressure monitor mounted onto and below the valve stem.

[0139]FIG. 14A is a sectioned view of the SAW tire pressure andtemperature monitor of FIG. 14 incorporating an absolute pressure SAWdevice.

[0140]FIG. 14B is a sectioned view of the SAW tire pressure andtemperature monitor of FIG. 14 incorporating a differential pressure SAWdevice.

[0141]FIG. 15 is a view of an accelerometer-based tire monitor alsoincorporating a SAW pressure and temperature monitor and cemented to theinterior of the tire opposite the tread.

[0142]FIG. 15A is a view of an accelerometer-based tire monitor alsoincorporating a SAW pressure and temperature monitor and inserted intothe tire opposite the tread during manufacture.

[0143]FIG. 16 is a detailed view of a polymer on SAW pressure sensor.

[0144]FIG. 16A is a view of a SAW temperature and pressure monitor on asingle SAW device.

[0145]FIG. 16B is a view of an alternate design of a SAW temperature andpressure monitor on a single SAW device.

[0146]FIG. 17 is a perspective view of a SAW temperature sensor.

[0147]FIG. 17A is a perspective view of a device that can provide twomeasurements of temperature or one of temperature and another of someother physical or chemical property such as pressure or chemicalconcentration.

[0148]FIG. 17B is a top view of an alternate SAW device capable ofdetermining two physical or chemical properties such as pressure andtemperature.

[0149]FIGS. 18 and 18A are views of a prior art SAW accelerometer thatcan be used for the tire monitor assembly of FIG. 15.

[0150]FIGS. 19A, 19B, 19C, 19D and 19E are views of occupant seat weightsensors using a slot spanning SAW strain gage and other strainconcentrating designs.

[0151]FIG. 20A is a view of a view of a SAW switch sensor for mountingon or within a surface such as a vehicle armrest.

[0152]FIG. 20B is a detailed perspective view of the device of FIG. 20Awith the force-transmitting member rendered transparent.

[0153]FIG. 20C is a detailed perspective view of an alternate SAW devicefor use in FIGS. 20A and 20B showing the use of one of two possibleswitches, one that activates the SAW and the other that suppresses theSAW.

[0154]FIG. 21A is a detailed perspective view of a polymer and mass onSAW accelerometer for use in crash sensors, vehicle navigation, etc.

[0155]FIG. 21B is a detailed perspective view of a normal mass on SAWaccelerometer for use in crash sensors, vehicle navigation, etc.

[0156]FIG. 22 is a view of a prior art SAW gyroscope that can be usedwith this invention.

[0157]FIG. 23A, 23B and 23C are a block diagrams of three interrogatorsthat can be used with this invention to interrogate several differentdevices.

[0158]FIG. 24 is a perspective view of a SAW antenna system adapted formounting underneath a vehicle and for communicating with the fourmounted tires.

[0159]FIG. 24A is a detail view of an antenna system for use in thesystem of FIG. 24.

[0160]FIG. 25 is an overhead view of a roadway with vehicles and a SAWroad temperature and humidity monitoring sensor.

[0161]FIG. 25A is a detail drawing of the monitoring sensor of FIG. 25.

[0162]FIG. 26 is a perspective view of a SAW system for locating avehicle on a roadway, and on the earth surface if accurate maps areavailable. It also illustrates the use of a SAW transponder in thelicense plate for the location of preceding vehicles and preventing rearend impacts.

[0163]FIG. 27 is a partial cutaway view of a section of a fluidreservoir with a SAW fluid pressure and temperature sensor formonitoring oil, water, or other fluid pressure.

[0164]FIG. 28 is a perspective view of a vehicle suspension system withSAW load sensors.

[0165]FIG. 28A is a cross section detail view of a vehicle spring andshock absorber system with a SAW torque sensor system mounted formeasuring the stress in the vehicle spring of the suspension system ofFIG. 28.

[0166]FIG. 28B is a detail view of a SAW torque sensor and shaftcompression sensor arrangement for use with the arrangement of FIG. 28.

[0167]FIG. 29 is a cutaway view of a vehicle showing possible mountinglocations for vehicle interior temperature, humidity, carbon dioxide,carbon monoxide, alcohol or other chemical or physical propertymeasuring sensors.

[0168]FIG. 30A is a perspective view of a SAW tilt sensor using four SAWassemblies for tilt measurement and one for temperature.

[0169]FIG. 30B is a top view of a SAW tilt sensor using three SAWassemblies for tilt measurement each one of which can also measuretemperature.

[0170]FIG. 31 is a perspective exploded view of a SAW crash sensor forsensing frontal, side or rear crashes.

[0171]FIG. 32 is a partial cutaway view of a piezoelectric generator andtire monitor using PVDF film.

[0172]FIG. 32A is a cutaway view of the PVDF sensor of FIG. 32.

[0173]FIG. 33 is a perspective view with portions cutaway of a SAW basedvehicle gas gage.

[0174]FIG. 33A is a top detailed view of a SAW pressure and temperaturemonitor for use in the system of FIG. 33.

[0175]FIG. 34 is a partial cutaway view of a vehicle drives wearing aseatbelt with SAW force sensors.

[0176]FIG. 35 is an alternate arrangement of a SAW tire pressure andtemperature monitor installed in the wheel rim facing inside.

[0177]FIG. 35A is a schematic of a prior art deployment scheme for anairbag module.

[0178]FIG. 36B is a schematic of a deployment scheme for an airbagmodule in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0179] As noted above, the invention relates generally to telematics andthe transmission of information from a vehicle to one or more remotesites which can react to the position or status of the vehicle oroccupant(s) therein.

[0180] Initially, sensing of the occupancy of the vehicle and theoptional transmission of this information, which may include images, toremote locations will be discussed. This entails obtaining informationfrom various sensors about the occupants in the passenger compartment ofthe vehicle, e.g., the number of occupants, their type and their motion,if any. Thereafter, a discussion of general vehicle diagnostic methodswill be discussed with the diagnosis being transmittable via acommunications device to the remote locations. Finally, an extensivediscussion of various sensors for use on the vehicle to sense differentoperating parameters and conditions of the vehicle is provided. All ofthe sensors discussed herein can be coupled to a communications deviceenabling transmission of data, signals and/or images to the remotelocations, and reception of the same from the remote locations.

[0181] Referring to the accompanying drawings wherein the same referencenumerals refer to the same or similar elements, FIG. 1 is a side view,with parts cutaway and removed of a vehicle showing the passengercompartment containing a rear facing child seat 610 on a front passengerseat 620 and one mounting location for a first embodiment of a vehicleinterior monitoring system in accordance with the invention. Theinterior monitoring system is capable of detecting the presence of anobject, determining the type of object, determining the location of theobject, and/or determining another property or characteristic of theobject. A property of the object could be the orientation of a childseat, the velocity of an adult and the like. For example, the vehicleinterior monitoring system can determine that an object is present onthe seat, that the object is a child seat and that the child seat isrear-facing. The vehicle interior monitoring system could also determinethat the object is an adult, that he is drunk and that he is out ofposition relative to the airbag.

[0182] In this embodiment, six transducers 631, 632, 633, 640, 641 and646 are used, although any number of transducers may be used. Eachtransducer 631, 632, 633, 640, 641, 646 may comprise only a transmitterwhich transmits energy, waves or radiation, only a receiver whichreceives energy, waves or radiation, both a transmitter and a receivercapable of transmitting and receiving energy, waves or radiation, anelectric field sensor, a capacitive sensor, or a self-tuningantenna-based sensor, weight sensor, chemical sensor, motion sensor orvibration sensor, for example.

[0183] Such transducers or receivers may be of the type which emit orreceive a continuous signal, a time varying signal (such as a capacitoror electric field sensor) or a spacial varying signal such as in ascanning system. One particular type of radiation-receiving receiver foruse in the invention is a receiver capable of receiving electromagneticwaves.

[0184] When ultrasonic energy is used, transducer 632 can be used as atransmitter and transducers 631,633 as receivers. Naturally, othercombinations can be used such as where all transducers are transceivers(transmitters and receivers). For example, transducer 632 can beconstructed to transmit ultrasonic energy toward the front passengerseat, which is modified, in this case by the occupying item of thepassenger seat, i.e., the rear facing child seat 610, and the modifiedwaves are received by the transducers 631 and 633, for example. A morecommon arrangement is where transducers 631, 632 and 633 are alltransceivers. Modification of the ultrasonic energy may constitutereflection of the ultrasonic energy as the ultrasonic energy isreflected back by the occupying item of the seat. The waves received bytransducers 631 and 633 vary with time depending on the shape of theobject occupying the passenger seat, in this case the rear facing childseat 610. Each object will reflect back waves having a differentpattern. Also, the pattern of waves received by transducer 631 willdiffer from the pattern received by transducer 633 in view of itsdifferent mounting location. This difference generally permits thedetermination of location of the reflecting surface (i.e., the rearfacing child seat 610) through triangulation. Through the use of twotransducers 631,633, a sort of stereographic image is received by thetwo transducers and recorded for analysis by processor 601, which iscoupled to the transducers 631,632,633. This image will differ for eachobject that is placed on the vehicle seat and it will also change foreach position of a particular object and for each position of thevehicle seat. Elements 631, 632, 633, although described as transducers,are representative of any type of component used in a wave-basedanalysis technique.

[0185] Mention is made above of the use of wave-type sensors as thetransducers 631, 632, 633 as well as electric field sensors. Electricfield sensors and wave sensors are essentially the same from the pointof view of sensing the presence of an occupant in a vehicle. In bothcases, a time varying electric field is disturbed or modified by thepresence of the occupant. At high frequencies in the visual, infraredand high frequency radio wave region, the sensor is based on itscapability to sense change of wave characteristics of theelectromagnetic field, such as amplitude, phase or frequency. As thefrequency drops, other characteristics of the field are measured. Atstill lower frequencies, the occupant's dielectric properties modifyparameters of the reactive electric field in the occupied spacebetween/near the plates of a capacitor. In this latter case, the sensorsenses the change in charge distribution on the capacitor plates bymeasuring, for example, the current wave magnitude or phase in theelectric circuit that drives the capacitor. These measured parametersare directly connected with parameters of the displacement current inthe occupied space. In all cases, the presence of the occupant reflects,absorbs or modifies the waves or variations in the electric field in thespace occupied by the occupant. Thus for the purposes of this invention,capacitance, electric field or electromagnetic wave sensors areequivalent and although they are all technically “field” sensors theywill be considered as “wave” sensors herein. What follows is adiscussion comparing the similarities and differences between two typesof field or wave sensors, electromagnetic wave sensors and capacitivesensors as exemplified by Kithil in U.S. Pat. No. 5,702,634.

[0186] An electromagnetic field disturbed or emitted by a passenger inthe case of an electromagnetic wave sensor, for example, and theelectric field sensor of Kithil, for example, are in many ways similarand equivalent for the purposes of this invention. The electromagneticwave sensor is an actual electromagnetic wave sensor by definitionbecause they sense parameters of a wave, which is a coupled pair ofcontinuously changing electric and magnetic fields. The electric fieldhere is not a static, potential one. It is essentially a dynamic,rotational electric field coupled with a changing magnetic one, that is,an electromagnetic wave. It cannot be produced by a steady distributionof electric charges. It is initially produced by moving electric chargesin a transmitter, even if this transmitter is a passenger body for thecase of a passive infrared sensor.

[0187] In the Kithil sensor, a static electric field is declared as aninitial material agent coupling a passenger and a sensor (see Column 5,lines 5-7): “The proximity sensor 12 each function by creating anelectrostatic field between oscillator input loop 54 and detector outputloop 56, which is affected by presence of a person near by, as a resultof capacitive coupling, . . . ”). It is a potential, non-rotationalelectric field. It is not necessarily coupled with any magnetic field.It is the electric field of a capacitor. It can be produced with asteady distribution of electric charges. Thus, it is not anelectromagnetic wave by definition but if the sensor is driven by avarying current, then it produces a quasistatic electric field in thespace between/near the plates of the capacitor.

[0188] Kithil declares that his capacitance sensor uses a staticelectric field. Thus, from the consideration above, one can concludethat Kithil's sensor cannot be treated as a wave sensor because thereare no actual electromagnetic waves but only a static electric field ofthe capacitor in the sensor system. However, this is not believed to bethe case. The Kithil system could not operate with a true staticelectric field because a steady system does not carry any information.Therefore, Kithil is forced to use an oscillator, causing an alternatecurrent in the capacitor and a reactive quasi-static electric field inthe space between the capacitor plates, and a detector to reveal aninformative change of the sensor capacitance caused by the presence ofan occupant (see FIG. 7 and its description). In this case, the systembecomes a “wave sensor” in the sense that it starts generating actualtime-varying electric field that certainly originates electromagneticwaves according to the definition above. That is, Kithil's sensor can betreated as a wave sensor regardless of the shape of the electric fieldthat it creates, a beam or a spread shape.

[0189] As follows from the Kithil patent, the capacitor sensor is likelya parametric system where the capacitance of the sensor is controlled byinfluence of the passenger body. This influence is transferred by meansof the near electromagnetic field (i.e., the wave-like process) couplingthe capacitor electrodes and the body. It is important to note that thesame influence takes place with a real static electric field also, thatis in absence of any wave phenomenon. This would be a situation if therewere no oscillator in Kithil's system. However, such a system is notworkable and thus Kithil reverts to a dynamic system using time-varyingelectric fields.

[0190] Thus, although Kithil declares the coupling is due to a staticelectric field, such a situation is not realized in his system becausean alternating electromagnetic field (“quasi-wave”) exists in the systemdue to the oscillator. Thus, his sensor is actually a wave sensor, thatis, it is sensitive to a change of a wave field in the vehiclecompartment. This change is measured by measuring the change of itscapacitance. The capacitance of the sensor system is determined by theconfiguration of its electrodes, one of which is a human body, that is,the passenger inside of and the part which controls the electrodeconfiguration and hence a sensor parameter, the capacitance.

[0191] The physics definition of “wave” from Webster's EncyclopedicUnabridged Dictionary is: “11. Physics. A progressive disturbancepropagated from point to point in a medium or space without progress oradvance of the points themselves, . . . ”. In a capacitor, the time thatit takes for the disturbance (a change in voltage) to propagate throughspace, the dielectric and to the opposite plate is generally small andneglected but it is not zero. As the frequency driving the capacitorincreases and the distance separating the plates increases, thistransmission time as a percentage of the period of oscillation canbecome significant. Nevertheless, an observer between the plates willsee the rise and fall of the electric field much like a person standingin the water of an ocean. The presence of a dielectric body between theplates causes the waves to get bigger as more electrons flow to and fromthe plates of the capacitor. Thus, an occupant affects the magnitude ofthese waves which is sensed by the capacitor circuit. Thus, theelectromagnetic field is a material agent that carries information abouta passenger's position in both Kithil's and a beam-type electromagneticwave sensor.

[0192] For ultrasonic systems, the “image” recorded from each ultrasonictransducer/receiver, is actually a time series of digitized data of theamplitude of the received signal versus time. Since there are tworeceivers, two time series are obtained which are processed by theprocessor 601. The processor 601 may include electronic circuitry andassociated, embedded software. Processor 601 constitutes one form ofgenerating means in accordance with the invention which generatesinformation about the occupancy of the passenger compartment based onthe waves received by the transducers 631,632,633.

[0193] When different objects are placed on the front passenger seat,the two images from transducers 631,633, for example, are different butthere are also similarities between all images of rear facing childseats, for example, regardless of where on the vehicle seat it is placedand regardless of what company manufactured the child seat. Alternately,there will be similarities between all images of people sitting on theseat regardless of what they are wearing, their age or size. The problemis to find the “rules” which differentiate the images of one type ofobject from the images of other types of objects, e.g., whichdifferentiate the occupant images from the rear facing child seatimages. The similarities of these images for various child seats arefrequently not obvious to a person looking at plots of the time seriesand thus computer algorithms are developed to sort out the variouspatterns. For a more detailed discussion of pattern recognition see U.S.Pat. No. 5,943,295 to Varga et. al., which is incorporated herein byreference.

[0194] The determination of these rules is important to the patternrecognition techniques used in this invention. In general, threeapproaches have been useful, artificial intelligence, fuzzy logic andartificial neural networks (including cellular and modular orcombination neural networks and support vector machines) (althoughadditional types of pattern recognition techniques may also be used,such as sensor fusion). In some implementations of this invention, suchas the determination that there is an object in the path of a closingwindow as described below, the rules are sufficiently obvious that atrained researcher can sometimes look at the returned signals and devisea simple algorithm to make the required determinations. In others, suchas the determination of the presence of a rear facing child seat or ofan occupant, artificial neural networks are used to determine the rules.One such set of neural network software for determining the patternrecognition rules is available from the NeuralWare Corporation ofPittsburgh, Pa.

[0195] The system used in a preferred implementation of this inventionfor the determination of the presence of a rear facing child seat, of anoccupant or of an empty seat is the artificial neural network. In thiscase, the network operates on the two returned signals as sensed bytransducers 631 and 633, for example. Through a training session, thesystem is taught to differentiate between the three cases. This is doneby conducting a large number of experiments where all possible childseats are placed in all possible orientations on the front passengerseat. Similarly, a sufficiently large number of experiments are run withhuman occupants and with boxes, bags of groceries and other objects(both inanimate and animate). Sometimes as many as 1,000,000 suchexperiments are run before the neural network is sufficiently trained sothat it can differentiate among the three cases and output the correctdecision with a very high probability. Of course, it must be realizedthat a neural network can also be trained to differentiate amongadditional cases, e.g., a forward facing child seat.

[0196] Once the network is determined, it is possible to examine theresult using tools supplied by NeuralWare or International ScientificResearch, for example, to determine the rules that were finally arrivedat by the trial and error techniques. In that case, the rules can thenbe programmed into a microprocessor resulting in a fuzzy logic or otherrule based system. Alternately, a neural computer, or cellular neuralnetwork, can be used to implement the net directly. In either case, theimplementation can be carried out by those skilled in the art of patternrecognition. If a microprocessor is used, a memory device is alsorequired to store the data from the analog to digital converters thatdigitize the data from the receiving transducers. On the other hand, ifa neural network computer is used, the analog signal can be fed directlyfrom the transducers to the neural network input nodes and anintermediate memory is not required. Memory of some type is needed tostore the computer programs in the case of the microprocessor system andif the neural computer is used for more than one task, a memory isneeded to store the network specific values associated with each task.

[0197] Electromagnetic energy based occupant sensors exist that use manyportions of the electromagnetic spectrum. A system based on theultraviolet, visible or infrared portions of the spectrum generallyoperate with a transmitter and a receiver of reflected radiation. Thereceiver may be a camera or a photo detector such as a pin or avalanchediode as described in detail in above-referenced patents and patentapplications. At other frequencies, the absorption of theelectromagnetic energy is primarily and at still other frequencies thecapacitance or electric field influencing effects are used. Generally,the human body will reflect, scatter, absorb or transmit electromagneticenergy in various degrees depending on the frequency of theelectromagnetic waves. All such occupant sensors are included herein.

[0198] In the embodiment wherein electromagnetic energy is used, it isto be appreciated that any portion of the electromagnetic signals thatimpinges upon, surrounds or involves a body portion of the occupant isat least partially absorbed by the body portion. Sometimes, this is dueto the fact that the human body is composed primarily of water, and thatelectromagnetic energy of certain frequencies is readily absorbed bywater. The amount of electromagnetic signal absorption is related to thefrequency of the signal, and size or bulk of the body portion that thesignal impinges upon. For example, a torso of a human body tends toabsorb a greater percentage of electromagnetic energy than a hand of ahuman body.

[0199] Thus, when electromagnetic waves or energy signals aretransmitted by a transmitter, the returning waves received by a receiverprovide an indication of the absorption of the electromagnetic energy.That is, absorption of electromagnetic energy will vary depending on thepresence or absence of a human occupant, the occupant's size, bulk,surface reflectivity, etc. depending on the frequency, so that differentsignals will be received relating to the degree or extent of absorptionby the occupying item on the seat. The receiver will produce a signalrepresentative of the returned waves or energy signals which will thusconstitute an absorption signal as it corresponds to the absorption ofelectromagnetic energy by the occupying item in the seat.

[0200] One or more of the transducers 631, 632, 633 can also beimage-receiving devices, such as cameras, which take images of theinterior of the passenger compartment. These images can be transmittedto a remote facility to monitor the passenger compartment or can bestored in a memory device for use in the event of an accident, i.e., todetermine the status of the occupants of the vehicle prior to theaccident. In this manner, it can be ascertained whether the driver wasfalling asleep, talking on the phone, etc.

[0201] A memory device for storing the images of the passengercompartment, and also for receiving and storing any of the otherinformation, parameters and variables relating to the vehicle oroccupancy of the vehicle, may be in the form a standardized “black box”(instead of or in addition to a memory part in a processor 601). TheIEEE Standards Association is currently beginning to develop aninternational standard for motor vehicle event data recorders. Theinformation stored in the black box and/or memory unit in the processor601, can include the images of the interior of the passenger compartmentas well as the number of occupants and the health state of theoccupants. The black box would preferably be tamper-proof andcrash-proof and enable retrieval of the information after a crash.

[0202]FIG. 2 shows schematically the interface between a vehicleinterior monitoring system in accordance with the invention and thevehicle's cellular or other telematics communication system. An adultoccupant 710 is shown sitting on the front passenger seat 720 and fourtransducers 731, 732, 640 and 641 are used to determine the presence (orabsence) of the occupant on that seat 720. One of the transducers 732 inthis case acts as both a transmitter and receiver while transducer 731acts only as a receiver. Alternately, transducer 731 could serve as botha transmitter and receiver or the transmitting function could bealternated between the two devices. Also, in many cases more that twotransmitters and receivers are used and in still other cases other typesof sensors, such as electric field, capacitance, self-tuning antennas(collectively represented by 140 and 141), weight, seatbelt, heartbeat,motion and seat position sensors, are also used in combination with theradiation sensors.

[0203] For a general object, transducers 731, 732, 140, 141 can also beused to determine the type of object, determine the location of theobject, and/or determine another property or characteristic of theobject. A property of the object could be the orientation of a childseat, the velocity of an adult and the like. For example, thetransducers 731, 732, 140, 141 can be designed to enable a determinationthat an object is present on the seat, that the object is a child seatand that the child seat is rear-facing.

[0204] The transducers 731 and 732 are attached to the vehicle buried inthe A-pillar trim, where their presence can be disguised, and areconnected to processor 601 that may also be hidden in the trim as shown(this being a non-limiting position for the processor 601). The A-pillaris the roof support pillar that is closest to the front of the vehicleand which, in addition to supporting the roof, also supports the frontwindshield and the front door. Other mounting locations can also beused. For example, transducers 731, 732 can be mounted inside the seat(along with or in place of transducers 140 and 141), in the ceiling ofthe vehicle, in the B-pillar, in the C-pillar and in the doors. Indeed,the vehicle interior monitoring system in accordance with the inventionmay comprise a plurality of monitoring units, each arranged to monitor aparticular seating location. In this case, for the rear seatinglocations, transducers might be mounted in the B-pillar or C-pillar orin the rear of the front seat or in the rear side doors. Possiblemounting locations for transducers, transmitters, receivers and otheroccupant sensing devices are disclosed in the above-referenced patentapplications and all of these mounting locations are contemplated foruse with the transducers described herein.

[0205] The cellular phone or other communications system 740 outputs toan antenna 750A. The transducers 731, 732, 140 and 141 in conjunctionwith the pattern recognition hardware and software, which is implementedin processor 601 and is packaged on a printed circuit board or flexcircuit along with the transducers 731 and 732, determine the presenceof an occupant within a few seconds after the vehicle is started, orwithin a few seconds after the door is closed. Similar systems locatedto monitor the remaining seats in the vehicle, also determine thepresence of occupants at the other seating locations and this result isstored in the computer memory which is part of each monitoring systemprocessor 601.

[0206] Periodically and in particular in the event of an accident, theelectronic system associated with the cellular phone system 740interrogates the various interior monitoring system memories and arrivesat a count of the number of occupants in the vehicle, and optionally,even makes a determination as to whether each occupant was wearing aseatbelt and if he or she is moving after the accident. The phone orother communications system then automatically dials the EMS operator(such as 911 or through a telematics service such as OnStart®) and theinformation obtained from the interior monitoring systems is forwardedso that a determination can be made as to the number of ambulances andother equipment to send to the accident site, for example. Such vehicleswill also have a system, such as the global positioning system, whichpermits the vehicle to determine its exact location and to forward thisinformation to the EMS operator.

[0207] Thus, in basic embodiments of the invention, wave or otherenergy-receiving transducers are arranged in the vehicle at appropriatelocations, trained if necessary depending on the particular embodiment,and function to determine whether a life form is present in the vehicleand if so, how many life forms are present and where they are locatedetc. To this end, transducers can be arranged to be operative at only asingle seating locations or at multiple seating locations with aprovision being made to eliminate repetitive count of occupants. Adetermination can also be made using the transducers as to whether thelife forms are humans, or more specifically, adults, child in childseas, etc. As noted above and below, this is possible using patternrecognition techniques. Moreover, the processor or processors associatedwith the transducers can be trained to determine the location of thelife forms, either periodically or continuously or possibly onlyimmediately before, during and after a crash. The location of the lifeforms can be as general or as specific as necessary depending on thesystem requirements, i.e., a determination can be made that a human issituated on the driver's seat in a normal position (general) or adetermination can be made that a human is situated on the driver's seatand is leaning forward and/or to the side at a specific angle as well asthe position of his or her extremities and head and chest(specifically). The degree of detail is limited by several factors,including, for example, the number and position of transducers andtraining of the pattern recognition algorithm.

[0208] In addition to the use of transducers to determine the presenceand location of occupants in a vehicle, other sensors could also beused. For example, a heartbeat sensor which determines the number andpresence of heartbeats can also be arranged in the vehicle, which wouldthus also determine the number of occupants as the number of occupantswould be equal to the number of heartbeats. Conventional heartbeatsensors can be adapted to differentiate between a heartbeat of an adult,a heartbeat of a child and a heartbeat of an animal. As its nameimplies, a heartbeat sensor detects a heartbeat, and the magnitudethereof, of a human occupant of the 'seat, if such a human occupant ispresent. The output of the heartbeat sensor is input to the processor ofthe interior monitoring system. One heartbeat sensor for use in theinvention may be of the types as disclosed in McEwan (U.S. Pat. Nos.5,573,012 and 5,766,208 which are incorporated herein in their entiretyby reference). The heartbeat sensor can be positioned at any convenientposition relative to the seats where occupancy is being monitored. Apreferred location is within the vehicle seatback.

[0209] An alternative way to determine the number of occupants is tomonitor the weight being applied to the seats, i.e., each seatinglocation, by arranging weight sensors at each seating location whichmight also be able to provide a weight distribution of an object on theseat. Analysis of the weight and/or weight distribution by apredetermined method can provide an indication of occupancy by a human,an adult or child, or an inanimate object.

[0210] Another type of sensor which is not believed to have been used inan interior monitoring system heretofore is a micropower impulse radar(MIR) sensor which determines motion of an occupant and thus candetermine his or her heartbeat (as evidenced by motion of the chest).Such an MIR sensor can be arranged to detect motion in a particular areain which the occupant's chest would most likely be situated or could becoupled to an arrangement which determines the location of theoccupant's chest and then adjusts the operational field of the MIRsensor based on the determined location of the occupant's chest. Amotion sensor utilizing a micro-power impulse radar (MIR) system asdisclosed, for example, in McEwan (U.S. Pat. No. 5,361,070, which isincorporated herein by reference), as well as many other patents by thesame inventor. Motion sensing is accomplished by monitoring a particularrange from the sensor as disclosed in that patent. MIR is one form ofradar which has applicability to occupant sensing and can be mounted atvarious locations in the vehicle. It has an advantage over ultrasonicsensors in that data can be acquired at a higher speed and thus themotion of an occupant can be more easily tracked. The ability to obtainreturns over the entire occupancy range is somewhat more difficult thanwith ultrasound resulting in a more expensive system overall. MIR hasadditional advantages in lack of sensitivity to temperature variationand has a comparable resolution to about 40 kHz ultrasound. Resolutioncomparable to higher frequency is also possible. Additionally, multipleMIR sensors can be used when high speed tracking of the motion of anoccupant during a crash is required since they can be individuallypulsed without interfering with each through time division multiplexing.

[0211] An alternative way to determine motion of the occupant(s) is tomonitor the weight distribution of the occupant whereby changes inweight distribution after an accident would be highly suggestive ofmovement of the occupant. A system for determining the weightdistribution of the occupants could be integrated or otherwise arrangedin the seats 620, 720 of the vehicle and several patents andpublications describe such systems.

[0212] More generally, any sensor which determines the presence andhealth state of an occupant can also be integrated into the vehicleinterior monitoring system in accordance with the invention. Forexample, a sensitive motion sensor can determine whether an occupant isbreathing and a chemical sensor can determine the amount of carbondioxide, or the concentration of carbon dioxide, in the air in thevehicle which can be correlated to the health state of the occupant(s).The motion sensor and chemical sensor can be designed to have a fixedoperational field situated where the occupant's mouth is most likely tobe located. In this manner, detection of carbon dioxide in the fixedoperational field could be used as an indication of the presence of ahuman occupant in order to enable the determination of the number ofoccupants in the vehicle. In the alternative, the motion sensor andchemical sensor can be adjustable and adapted to adjust theiroperational field in conjunction with a determination by an occupantposition and location sensor which would determine the location ofspecific parts of the occupant's body, e.g., his or her chest or mouthFurthermore, an occupant position and location sensor can be used todetermine the location of the occupant's eyes and determine whether theoccupant is conscious, i.e., whether his or her eyes are open or closedor moving.

[0213] The use of chemical sensors can also be used to detect whetherthere is blood present in the vehicle, for example, after an accident.Additionally, microphones can detect whether there is noise in thevehicle caused by groaning, yelling, etc., and transmit any such noisethrough the cellular or other communication connection to a remotelistening facility (such as operated by OnStar®.

[0214]FIG. 3 shows a schematic diagram of an embodiment of the inventionincluding a system for determining the presence and health state of anyoccupants of the vehicle and a telecommunications link. This embodimentincludes means for determining the presence of any occupants 410 whichmay take the form of a heartbeat sensor or motion sensor as describedabove and means for determining the health state of any occupants 412.The latter means may be integrated into the means for determining thepresence of any occupants, i.e., one and the same component, or separatetherefrom. Further, means for determining the location, and optionallyvelocity, of the occupants or one or more parts thereof 414 are providedand may be any conventional occupant position sensor or preferably, oneof the occupant position sensors as described herein (e.g., thoseutilizing waves. electromagnetic radiation or electric fields) or asdescribed in the current assignee's patents and patent applicationsreferenced above.

[0215] A processor 416 is coupled to the presence determining means 410,the health state determining means 412 and the location determiningmeans 414. A communications unit 418 is coupled to the processor 416.The processor 416 and/or communications unit 418 can also be coupled tomicrophones 420 that can be distributed throughout the vehicle andinclude voice-processing circuitry to enable the occupant(s) to effectvocal control of the processor 416, communications unit 418 or anycoupled component or oral communications via the communications unit418. The processor 416 is also coupled to another vehicular system,component or subsystem 422 and can issue control commands to effectadjustment of the operating conditions of the system, component orsubsystem. Such a system, component or subsystem can be the heating orair-conditioning system, the entertainment system, an occupant restraintdevice such as an airbag, a glare prevention system, etc. Also, apositioning system 424 could be coupled to the processor 416 andprovides an indication of the absolute position of the vehicle,preferably using satellite-based positioning technology (e.g., a GPSreceiver).

[0216] In normal use (other than after a crash), the presencedetermining means 410 determine whether any human occupants are present,i.e., adults or children, and the location determining means 414determine the occupant's location. The processor 416 receives signalsrepresentative of the presence of occupants and their location anddetermines whether the vehicular system, component or subsystem 422 canbe modified to optimize its operation for the specific arrangement ofoccupants. For example, if the processor 416 determines that only thefront seats in the vehicle are occupied, it could control the heatingsystem to provide heat only through vents situated to provide heat forthe front-seated occupants.

[0217] Another possible vehicular system, component or subsystem is anavigational aid, i.e., a route display or map. In this case, theposition of the vehicle as determined by the positioning system 424 isconveyed through processor 416 to the communications unit 418 to aremote facility and a map is transmitted from this facility to thevehicle to be displayed on the route display. If directions are needed,a request for the same could be entered into an input unit 426associated with the processor 416 and transmitted to the facility. Datafor the display map and/or vocal instructions could be transmitted fromthis facility to the vehicle.

[0218] Moreover, using this embodiment, it is possible to remotelymonitor the health state of the occupants in the vehicle and mostimportantly, the driver. The health state determining means 412 may beused to detect whether the driver's breathing is erratic or indicativeof a state in which the driver is dozing off. The health statedetermining means 412 could also include a breath-analyzer to determinewhether the driver's breath contains alcohol. In this case, the healthstate of the driver is relayed through the processor 416 and thecommunications unit 418 to the remote facility and appropriate actioncan be taken. For example, it would be possible to transmit a command tothe vehicle to activate an alarm or illuminate a warning light or if thevehicle is equipped with an automatic guidance system and ignitionshut-off, to cause the vehicle to come to a stop on the shoulder of theroadway or elsewhere out of the traffic stream. The alarm, warninglight, automatic guidance system and ignition shut-off are thusparticular vehicular components or subsystems represented by 422.

[0219] In use after a crash, the presence determining means 410, healthstate determining means 412 and location determining means 414 canobtain readings from the passenger compartment and direct such readingsto the processor 416. The processor 416 analyzes the information anddirects or controls the transmission of the information about theoccupant(s) to a remote, manned facility. Such information would includethe number and type of occupants, i.e., adults, children, infants,whether any of the occupants have stopped breathing or are breathingerratically, whether the occupants are conscious (as evidenced by, e.g.,eye motion), whether blood is present (as detected by a chemical sensor)and whether the occupants are making noise. Moreover, the communicationslink through the communications unit 418 can be activated immediatelyafter the crash to enable personnel at the remote facility to initiatecommunications with the vehicle.

[0220] An occupant sensing system can also involve sensing for thepresence of a living occupant in a trunk of a vehicle or in a closedvehicle, for example, when a child is inadvertently left in the vehicleor enters the trunk and the trunk closes. To this end, a SAW-basedchemical sensor 250 is illustrated in FIG. 4A for mounting in a vehicletrunk as illustrated in FIG. 4. The chemical sensor 250 is designed tomeasure carbon dioxide concentration through the mass loading effects asdescribed in U.S. Pat. No. 4,895,017, which is incorporated by referenceherein, with a polymer coating selected that is sensitive to carbondioxide. The speed of the surface acoustic wave is a function of thecarbon dioxide level in the atmosphere. Section 252 of the chemicalsensor 250 contains a coating of such a polymer and the acousticvelocity in this section is a measure of the carbon dioxideconcentration. Temperature effects are eliminated through a comparisonof the sonic velocities in sections 251 and 252 as described above.

[0221] Thus, when trunk lid 260 is closed and a source of carbon dioxidesuch as a child or animal is trapped within the trunk, the chemicalsensor 250 will provide information indicating the presence of thecarbon dioxide producing object to the interrogator which can thenrelease the trunk lock permitting trunk to automatically open. In thismanner, the problem of children and animals suffocating in closed trunksis eliminated. Alternately, information that a person or animal istrapped in a trunk can be sent by the telematics system to lawenforcement authorities or other location remote from the vehicle.

[0222] A similar device can be distributed at various locations withinthe passenger compartment of vehicle along with a combined temperaturesensor. If the car has been left with a child or other animal whileowner is shopping, for example, and if the temperature rises within thevehicle to an unsafe level or, alternately, if the temperature dropsbelow an unsafe level, then the vehicle can be signaled to takeappropriate action which may involve opening the windows or starting thevehicle with either air conditioning or heating as appropriate.Alternately, information that a person or animal is trapped within avehicle can be sent by the telematics system to law enforcementauthorities or other location remote from the vehicle. Thus, throughthese simple wireless powerless sensors, the problem of suffocationeither from lack of oxygen or death from excessive heat or cold can allbe solved in a simple, low-cost manner through using an interrogator asdisclosed in the current assignee's U.S. patent application Ser. No.10/079,065 incorporated by reference herein in its entirety.

[0223] Additionally, a sensitive layer on a SAW can be made to besensitive to other chemicals such as water vapor for humidity control oralcohol for drunk driving control. Similarly, the sensitive layer can bedesigned to be sensitive to carbon monoxide thereby preventing carbonmonoxide poisoning. Many other chemicals can be sensed for specificapplications such as to check for chemical leaks in commercial vehicles,for example. Whenever such a sensor system determines that a dangeroussituation is developing, an alarm can be sounded and/or the situationcan be automatically communicated to an off vehicle location throughtelematics, a cell phone such as a 911 call, the Internet or though asubscriber service such as OnStar®.

[0224] Described above is a system for determining the status ofoccupants in a vehicle, and in the event of an accident or at any otherappropriate time, transmitting the status of the occupants, andoptionally additional information, via a communications channel or linkto a remote monitoring facility. In addition to the status of theoccupant, it is also important to be able to analyze the operatingconditions of the vehicle and detect when a component of the vehicle isabout to fail. By notifying the driver of the impending failure of thecomponent, appropriate corrective action can be taken to avoid suchfailure.

[0225] The operating conditions of the vehicle can also be transmittedalong with the status of the occupants to a remote monitoring facility.The operating conditions of the vehicle include whether the motor isrunning and whether the vehicle is moving. Thus, in a general embodimentin which information on both occupancy of the vehicle and the operatingconditions of the vehicle are transmitted, one or more properties orcharacteristics of occupancy of the vehicle are determined, suchconstituting information about the occupancy of the vehicle, and one ormore states of the vehicle or of a component of the vehicle isdetermined, such constituting information about the operation of thevehicle. The information about the occupancy of the vehicle andoperation of the vehicle are selectively transmitted, possibly theinformation about occupancy to an emergency response center and theinformation about the vehicle to a dealer or repair facility.

[0226] Transmission of the information about the operation of thevehicle, i.e., diagnostic information, may be achieved via a satelliteand/or via the Internet. The vehicle would thus include appropriateelectronic hardware and/or software to enable the transmission of asignal to a satellite, from where it could be re-transmitted to a remotelocation, and/or to enable the transmission to a web site or hostcomputer. In the latter case, the vehicle could be assigned a domainname or e-mail address for identification or transmission originationpurposes

[0227] It is important to appreciate that the preferred embodiment ofthe vehicle diagnostic unit described below performs the diagnosis,i.e., processes the input from the various sensors, on the vehicle usingfor example a processor embodying a pattern recognition technique suchas a neural network. The processor thus receives data or signals fromthe sensors and generates an output indicative or representative of theoperating conditions of the vehicle or its component. A signal couldthus be generated indicative of an underinflated tire, or an overheatingengine.

[0228] For the discussion below, the following terms are defined asfollows:

[0229] The term “component” refers to any part or assembly of partswhich is mounted to or a part of a motor vehicle and which is capable ofemitting a signal representative of its operating state. The followingis a partial list of general automobile and truck components, the listnot being exclusive:

[0230] engine;

[0231] transmission;

[0232] brakes and associated brake assembly;

[0233] tires;

[0234] wheel;

[0235] steering wheel and steering column assembly;

[0236] water pump;

[0237] alternator;

[0238] shock absorber;

[0239] wheel mounting assembly;

[0240] radiator;

[0241] battery;

[0242] oil pump;

[0243] fuel pump;

[0244] air conditioner compressor;

[0245] differential gear;

[0246] exhaust system;

[0247] fan belts;

[0248] engine valves;

[0249] steering assembly;

[0250] vehicle suspension including shock absorbers;

[0251] vehicle wiring system; and

[0252] engine cooling fan assembly.

[0253] The term “sensor” refers to any measuring or sensing devicemounted on a vehicle or any of its components including new sensorsmounted in conjunction with the diagnostic module in accordance with theinvention. A partial, non-exclusive list of common sensors mounted on anautomobile or truck is as follows:

[0254] airbag crash sensor;

[0255] accelerometer;

[0256] microphone;

[0257] camera;

[0258] antenna, capacitance sensor or other electromagnetic wave sensor;

[0259] stress or strain sensor;

[0260] pressure sensor;

[0261] weight sensor;

[0262] magnetic field sensor;

[0263] coolant thermometer;

[0264] oil pressure sensor;

[0265] oil level sensor;

[0266] air flow meter;

[0267] voltmeter;

[0268] ammeter;

[0269] humidity sensor;

[0270] engine knock sensor;

[0271] oil turbidity sensor;

[0272] throttle position sensor;

[0273] steering wheel torque sensor;

[0274] wheel speed sensor;

[0275] tachometer;

[0276] speedometer;

[0277] other velocity sensors;

[0278] other position or displacement sensors;

[0279] oxygen sensor;

[0280] yaw, pitch and roll angular sensors;

[0281] clock;

[0282] odometer;

[0283] power steering pressure sensor;

[0284] pollution sensor;

[0285] fuel gauge;

[0286] cabin thermometer;

[0287] transmission fluid level sensor;

[0288] gyroscopes or other angular rate sensors including yaw, pitch androll rate sensors;

[0289] coolant level sensor;

[0290] transmission fluid turbidity sensor;

[0291] break pressure sensor;

[0292] tire pressure sensor;

[0293] tire temperature sensor, and

[0294] coolant pressure sensor.

[0295] The term “signal” herein refers to any time varying output from acomponent including electrical, acoustic, thermal, or electromagneticradiation, or mechanical vibration.

[0296] Sensors on a vehicle are generally designed to measure particularparameters of particular vehicle components. However, frequently thesesensors also measure outputs from other vehicle components. For example,electronic airbag crash sensors currently in use contain anaccelerometer for determining the accelerations of the vehicle structureso that the associated electronic circuitry of the airbag crash sensorcan determine whether a vehicle is experiencing a crash of sufficientmagnitude so as to require deployment of the airbag. This accelerometercontinuously monitors the vibrations in the vehicle structure regardlessof the source of these vibrations. If a wheel is out of balance, or ifthere is extensive wear of the parts of the front wheel mountingassembly, or wear in the shock absorbers, the resulting abnormalvibrations or accelerations can, in many cases, be sensed by the crashsensor accelerometer. There are other cases, however, where thesensitivity or location of the airbag crash sensor accelerometer is notappropriate and one or more additional accelerometers may be mountedonto a vehicle for the purposes of this invention. Some airbag crashsensors are not sufficiently sensitive accelerometers or have sufficientdynamic range for the purposes herein.

[0297] Every component of a vehicle emits various signals during itslife. These signals can take the form of electromagnetic radiation,acoustic radiation, thermal radiation, vibrations transmitted throughthe vehicle structure, and voltage or current fluctuations, depending onthe particular component. When a component is functioning normally, itmay not emit a perceptible signal. In that case, the normal signal is nosignal, i.e., the absence of a signal. In most cases, a component willemit signals that change over its life and it is these changes whichcontain information as to the state of the component, e.g., whetherfailure of the component is impending. Usually components do not failwithout warning. However, most such warnings are either not perceived orif perceived are not understood by the vehicle operator until thecomponent actually fails and, in some cases, a breakdown of the vehicleoccurs. In a few years, it is expected that various roadways will havesystems for automatically guiding vehicles operating thereon. Suchsystems have been called “smart highways” and are part of the field ofintelligent transportation systems (ITS). If a vehicle operating on sucha smart highway were to breakdown, serious disruption of the systemcould result and the safety of other users of the smart highway could beendangered.

[0298] In accordance with the invention, each of these signals emittedby the vehicle components is converted into electrical signals and thendigitized (i.e., the analog signal is converted into a digital signal)to create numerical time series data which is then entered into aprocessor. Pattern recognition algorithms then are applied in theprocessor to attempt to identify and classify patterns in this timeseries data. For a particular component, such as a tire for example, thealgorithm attempts to determine from the relevant digital data whetherthe tire is functioning properly or whether it requires balancing,additional air, or perhaps replacement.

[0299] Frequently, the data entered into the computer needs to bepreprocessed before being analyzed by a pattern recognition algorithm.The data from a wheel speed sensor, for example, might be used as is fordetermining whether a particular tire is operating abnormally in theevent it is unbalanced, whereas the integral of the wheel speed dataover a long time period (a preprocessing step), when compared to suchsensors on different wheels, might be more useful in determining whethera particular tire is going flat and therefore needs air. In some cases,the frequencies present in a set of data are a better predictor ofcomponent failures than the data itself. For example, when a motorbegins to fail due to worn bearings, certain characteristic frequenciesbegan to appear. In most cases, the vibrations arising from rotatingcomponents, such as the engine, will be normalized based on therotational frequency as disclosed in the NASA TSP referenced above.Moreover, the identification of which component is causing vibrationspresent in the vehicle structure can frequently be accomplished througha frequency analysis of the data. For these cases, a Fouriertransformation of the data is made prior to entry of the data into apattern recognition algorithm. Other mathematical transformations arealso made for particular pattern recognition purposes in practicing theteachings of this invention. Some of these include shifting andcombining data to determine phase changes for example, differentiatingthe data, filtering the data, and sampling the data. Also, there existcertain more sophisticated mathematical operations that attempt toextract or highlight specific features of the data. This inventioncontemplates the use of a variety of these preprocessing techniques andthe choice of which ones is left to the skill of the practitionerdesigning a particular diagnostic module.

[0300] Another technique that is contemplated for some implementationsof this invention is the use of multiple accelerometers and/ormicrophones that will allow the system to locate the source of anymeasured vibrations based on the time of flight and/or triangulationtechniques. Once a distributed accelerometer installation has beenimplemented to permit this source location, the same sensors can be usedfor smarter crash sensing as it will permit the determination of thelocation of the impact on the vehicle. Once the impact location isknown, a highly tailored algorithm can be used to accurately forecastthe crash severity making use of a knowledge on the force vs. crushproperties of the vehicle at the impact location.

[0301] When a vehicle component begins to change its operating behavior,it is not always apparent from the particular sensors, if any, which aremonitoring that component. The output from any one of these sensors canbe normal even though the component is failing. By analyzing the outputof a variety of sensors, however, the pending failure can be diagnosed.For example, the rate of temperature rise in the vehicle coolant, if itwere monitored, might appear normal unless it were known that thevehicle was idling and not traveling down a highway at a high speed.Even the level of coolant temperature which is in the normal range couldbe in fact abnormal in some situations signifying a failing coolantpump, for example, but not detectable from the coolant thermometeralone.

[0302] The pending failure of some components is difficult to diagnoseand sometimes the design of the component requires modification so thatthe diagnosis can be more readily made. A fan belt, for example,frequently begins failing by a cracking of the inner surface. The beltcan be designed to provide a sonic or electrical signal when thiscracking begins in a variety of ways. Similarly, coolant hoses can bedesigned with an intentional weak spot where failure will occur first ina controlled manner that can also cause a whistle sound as a smallamount of steam exits from the hose. This whistle sound can then besensed by a general purpose microphone, for example.

[0303] In FIG. 5, a generalized component 800 emitting several signalswhich are transmitted along a variety of paths, sensed by a variety ofsensors and analyzed by the diagnostic device in accordance with theinvention is illustrated schematically. Component 800 is mounted to avehicle 880 and during operation it emits a variety of signals such asacoustic 801, electromagnetic radiation 802, thermal radiation 803,current and voltage fluctuations in conductor 804 and mechanicalvibrations 805. Various sensors are mounted in the vehicle to detect thesignals emitted by the component 800. These include one or morevibration sensors (accelerometers) 830, 850 and/or gyroscopes alsomounted to the vehicle, one or more acoustic sensors 810, 851,electromagnetic radiation sensor 815, heat radiation sensor 820, andvoltage or current sensor 840.

[0304] In addition, various other sensors 852, 853 measure otherparameters of other components that in some manner provide informationdirectly or indirectly on the operation of component 800. All of thesensors illustrated on FIG. 5 can be connected to a data bus 860. Adiagnostic module 870, in accordance with the invention, can also beattached to the vehicle data bus 860 and receives the signals generatedby the various sensors. The sensors may however be wirelessly connectedto the diagnostic module 870 and be integrated into a wireless power andcommunications system or a combination of wired and wirelessconnections.

[0305] As shown in FIG. 5, the diagnostic module 870 has access to theoutput data of each of the sensors that have information relative to thecomponent 800. This data appears as a series of numerical values eachcorresponding to a measured value at a specific point in time. Thecumulative data from a particular sensor is called a time series ofindividual data points. The diagnostic module 870 compares the patternsof data received from each sensor individually, or in combination withdata from other sensors, with patterns for which the diagnostic modulehas been trained to determine whether the component is functioningnormally or abnormally.

[0306] Important to this invention is the manner in which the diagnosticmodule 870 determines a normal pattern from an abnormal pattern and themanner in which it decides what data to use from the vast amount of dataavailable. This is accomplished using pattern recognition technologiessuch as artificial neural networks and training. The theory of neuralnetworks including many examples can be found in several books on thesubject including: (1) Techniques And Application Of Neural Networks,edited by Taylor, M. and Lisboa, P., Ellis Horwood, West Sussex,England, 1993; (2) Naturally Intelligent Systems, by Caudill, M. andButler, C., MIT Press, Cambridge Mass., 1990; (3) J. M. Zaruda,Introduction to Artificial Neural Systems, West publishing Co., N.Y.,1992, (4) Digital Neural Networks, by Kung, S. Y., PTR Prentice Hall,Englewood Cliffs, N.J., 1993, Eberhart, R., Simpson, P., (5) Dobbins,R., Computational Intelligence PC Tools, Academic Press, Inc., 1996,Orlando, Fla., (6) Cristianini, N. and Shawe-Taylor, J. An Introductionto Support Vector Machines and other kernal-based learning methods,Cambridge University Press, Cambridge England, 2000; (7) Proceedings ofthe 2000 6^(th) IEEE International Workshop on Cellular Neural Networksand their Applications (CNNA 2000), IEEE, Piscataway N.J.; and (8)Sinha, N. K. and Gupta, M. M. Soft Computing & Intelligent Systems,Academic Press 2000 San Diego, Calif., all of which are incorporatedherein by reference. The neural network pattern recognition technologyis one of the most developed of pattern recognition technologies. Theinvention described herein frequently uses combinations of neuralnetworks to improve the pattern recognition process.

[0307] The neural network pattern recognition technology is one of themost developed of pattern recognition technologies. The neural networkwill be used here to illustrate one example of a pattern recognitiontechnology but it is emphasized that this invention is not limited toneural networks. Rather, the invention may apply any known patternrecognition technology including sensor fusion and various correlationtechnologies. A brief description of a particular example of a neuralnetwork pattern recognition technology is set forth below.

[0308] Neural networks are constructed of processing elements known asneurons that are interconnected using information channels callinterconnects. Each neuron can have multiple inputs but only one output.Each output however is usually connected to all other neurons in thenext layer. The neurons in the first layer operate collectively on theinput data as described in more detail below. Neural networks learn byextracting relational information from the data and the desired output.Neural networks have been applied to a wide variety of patternrecognition problems including automobile occupant sensing, speechrecognition, optical character recognition, and handwriting analysis.

[0309] To train a neural network, data is provided in the form of one ormore time series that represents the condition to be diagnosed as wellas normal operation. As an example, the simple case of an out of balancetire will be used. Various sensors on the vehicle can be used to extractinformation from signals emitted by the tire such as an accelerometer, atorque sensor on the steering wheel, the pressure output of the powersteering system, a tire pressure monitor or tire temperature monitor.Other sensors that might not have an obvious relationship to tireunbalance are also included such as, for example, the vehicle speed orwheel speed that can be determined from the ABS system. Data is takenfrom a variety of vehicles where the tires were accurately balancedunder a variety of operating conditions also for cases where varyingamounts of unbalance was intentionally introduced. Once the data hadbeen collected, some degree of preprocessing or feature extraction isusually performed to reduce the total amount of data fed to the neuralnetwork. In the case of the unbalanced tire, the time period betweendata points might be chosen such that there are at least ten data pointsper revolution of the wheel. For some other application, the time periodmight be one minute or one millisecond.

[0310] Once the data has been collected, it is processed by a neuralnetwork-generating program, for example, if a neural network patternrecognition system is to be used. Such programs are availablecommercially, e.g., from NeuralWare of Pittsburgh, Pa. or fromInternational Scientific Research, Inc., of Romeo Mich. for modularneural networks. The program proceeds in a trial and error manner untilit successfully associates the various patterns representative ofabnormal behavior, an unbalanced tire, with that condition. Theresulting neural network can be tested to determine if some of the inputdata from some of the sensors, for example, can be eliminated. In thisway, the engineer can determine what sensor data is relevant to aparticular diagnostic problem. The program then generates an algorithmthat is programmed onto a microprocessor, microcontroller, neuralprocessor, FPGA, or DSP (herein collectively referred to as amicroprocessor or processor). Such a microprocessor appears inside thediagnostic module 870 in FIG. 5. Once trained, the neural network, asrepresented by the algorithm, will now recognize an unbalanced tire on avehicle when this event occurs. At that time, when the tire isunbalanced, the diagnostic module 870 will output a message to thedriver indicating that the tire should be now be balanced as describedin more detail below. The message to the driver is provided by outputmeans coupled to or incorporated within the module 870 and may be, e.g.,a light on the dashboard, a vocal tone or any other recognizableindication apparatus. A similar message may also be sent to the dealeror other repair facility or remote facility.

[0311] It is important to note that there may be many neural networksinvolved in a total vehicle diagnostic system. These can be organizedeither in parallel, series, as an ensemble, cellular neural network oras a modular neural network system. In one implementation of a modularneural network, a primary neural network identifies that there is anabnormality and tries to identify the likely source. Once a choice hasbeen made as to the likely source of the abnormality, another of a groupof neural networks is called upon to determine the exact cause of theabnormality. In this manner, the neural networks are arranged in a treepattern with each neural network trained to perform a particular patternrecognition task.

[0312] Discussions on the operation of a neural network can be found inthe above references on the subject and are well understood by thoseskilled in the art. Neural networks are the most well known of thepattern recognition technologies based on training, although neuralnetworks have only recently received widespread attention and have beenapplied to only very limited and specialized problems in motor vehicles.Other non-training based pattern recognition technologies exist, such asfuzzy logic. However, the programming required to use fuzzy logic, wherethe patterns must be determine by the programmer, render these systemsimpractical for general vehicle diagnostic problems such as describedherein. Therefore, preferably the pattern recognition systems that learnby training are used herein.

[0313] The neural network is the first highly successful of what will bea variety of pattern recognition techniques based on training. There isnothing that suggests that it is the only or even the best technology.The characteristics of all of these technologies which render themapplicable to this general diagnostic problem include the use oftime-based input data and that they are trainable. In all cases, thepattern recognition technology learns from examples of datacharacteristic of normal and abnormal component operation.

[0314] A diagram of one example of a neural network used for diagnosingan unbalanced tire, for example, based on the teachings of thisinvention is shown in FIG. 6. The process can be programmed toperiodically test for an unbalanced tire. Since this need be done onlyinfrequently, the same processor can be used for many such diagnosticproblems. When the particular diagnostic test is run, data from thepreviously determined relevant sensors is preprocessed and analyzed withthe neural network algorithm. For the unbalanced tire, using the datafrom an accelerometer for example, the digital acceleration values fromthe analog to digital converter in the accelerometer are entered intonodes 1 through n and the neural network algorithm compares the patternof values on nodes 1 through n with patterns for which it has beentrained as follows.

[0315] Each of the input nodes is connected to each of the second layernodes, h-1,h-2, . . . ,h-n, called the hidden layer, either electricallyas in the case of a neural computer, or through mathematical functionscontaining multiplying coefficients called weights, in the mannerdescribed in more detail in the above references. At each hidden layernode, a summation occurs of the values from each of the input layernodes, which have been operated on by functions containing the weights,to create a node value. Similarly, the hidden layer nodes are in likemanner connected to the output layer node(s), which in this example isonly a single node 0 representing the decision to notify the driver,and/or a remote facility, of the unbalanced tire. During the trainingphase, an output node value of 1, for example, is assigned to indicatethat the driver should be notified and a value of 0 is assigned to notdoing so. Once again, the details of this process are described inabove-referenced texts and will not be presented in detail here.

[0316] In the example above, twenty input nodes were used, five hiddenlayer nodes and one output layer node. In this example, only one sensorwas considered and accelerations from only one direction were used. Ifother data from other sensors such as accelerations from the vertical orlateral directions were also used, then the number of input layer nodeswould increase. Again, the theory for determining the complexity of aneural network for a particular application has been the subject of manytechnical papers and will not be presented in detail here. Determiningthe requisite complexity for the example presented here can beaccomplished by those skilled in the art of neural network design.

[0317] Briefly, the neural network described above defines a method,using a pattern recognition system, of sensing an unbalanced tire anddetermining whether to notify the driver, and/or a remote facility, andcomprises the steps of:

[0318] (a) obtaining an acceleration signal from an accelerometermounted on a vehicle;

[0319] (b) converting the acceleration signal into a digital timeseries;

[0320] (c) entering the digital time series data into the input nodes ofthe neural network;

[0321] (d) performing a mathematical operation on the data from each ofthe input nodes and inputting the operated on data into a second seriesof nodes wherein the operation performed on each of the input node dataprior to inputting the operated on value to a second series node isdifferent from that operation performed on some other input node data;

[0322] (e) combining the operated on data from all of the input nodesinto each second series node to form a value at each second series node;

[0323] (f) performing a mathematical operation on each of the values onthe second series of nodes and inputting this operated on data into anoutput series of nodes wherein the operation performed on each of thesecond series node data prior to inputting the operated on value to anoutput series node is different from that operation performed on someother second series node data;

[0324] (g) combining the operated on data from all of the second seriesnodes into each output series node to form a value at each output seriesnode; and,

[0325] (h) notifying a driver if the value on one output series node iswithin a chosen range signifying that a tire requires balancing.

[0326] This method can be generalized to a method of predicting that acomponent of a vehicle will fail comprising the steps of:

[0327] (a) sensing a signal emitted from the component;

[0328] (b) converting the sensed signal into a digital time series;

[0329] (c) entering the digital time series data into a patternrecognition algorithm;

[0330] (d) executing the pattern recognition algorithm to determine ifthere exists within the digital time series data a patterncharacteristic of abnormal operation of the component; and

[0331] (e) notifying a driver and/or a remote facility if the abnormalpattern is recognized.

[0332] The particular neural network described and illustrated abovecontains a single series of hidden layer nodes. In some network designs,more than one hidden layer is used, although only rarely will more thantwo such layers appear. There are of course many other variations of theneural network architecture illustrated above which appear in thereferenced literature. For the purposes herein, therefore, “neuralnetwork” will be defined as a system wherein the data to be processed isseparated into discrete values which are then operated on and combinedin at least a two stage process and where the operation performed on thedata at each stage is in general different for each discrete value andwhere the operation performed is at least determined through a trainingprocess.

[0333] The implementation of neural networks can take on at least twoforms, an algorithm programmed on a digital microprocessor, FPGA, DSP orin a neural computer (including a cellular neural network or supportvector machine). In this regard, it is noted that neural computer chipsare now becoming available.

[0334] In the example above, only a single component failure wasdiscussed using only a single sensor since the data from the singlesensor contains a pattern which the neural network was trained torecognize as either normal operation of the component or abnormaloperation of the component. The diagnostic module 870 containspreprocessing and neural network algorithms for a number of componentfailures. The neural network algorithms are generally relatively simple,requiring only a relatively small number of lines of computer code. Asingle general neural network program can be used for multiple patternrecognition cases by specifying different coefficients for the variousterms, one set for each application. Thus, adding different diagnosticchecks has only a small affect on the cost of the system. Also, thesystem has available to it all of the information available on the databus. During the training process, the pattern recognition program sortsout from the available vehicle data on the data bus or from othersources, those patterns that predict failure of a particular component.

[0335] In FIG. 7, a schematic of a vehicle with several components andseveral sensors is shown in their approximate locations on a vehiclealong with a total vehicle diagnostic system in accordance with theinvention utilizing a diagnostic module in accordance with theinvention. A flow diagram of information passing from the varioussensors shown in FIG. 7 onto the vehicle data bus and thereby into thediagnostic device in accordance with the invention is shown in FIG. 8along with outputs to a display for notifying the driver and to thevehicle cellular phone, or other communication device, for notifying thedealer, vehicle manufacturer or other entity concerned with the failureof a component in the vehicle. If the vehicle is operating on a smarthighway, for example, the pending component failure information may alsobe communicated to a highway control system and/or to other vehicles inthe vicinity so that an orderly exiting of the vehicle from the smarthighway can be facilitated. FIG. 8 also contains the names of thesensors shown numbered on FIG. 7.

[0336] Sensor 901 is a crash sensor having an accelerometer (alternatelyone or more dedicated accelerometers 931 can be used), sensor 902 isrepresents one or more microphones, sensor 903 is a coolant thermometer,sensor 904 is an oil pressure sensor, sensor 905 is an oil level sensor,sensor 906 is an air flow meter, sensor 907 is a voltmeter, sensor 908is an ammeter, sensor 909 is a humidity sensor, sensor 910 is an engineknock sensor, sensor 911 is an oil turbidity sensor, sensor 912 is athrottle position sensor, sensor 913 is a steering torque sensor, sensor914 is a wheel speed sensor, sensor 915 is a tachometer, sensor 916 is aspeedometer, sensor 917 is an oxygen sensor, sensor 918 is a pitch/rollsensor, sensor 919 is a clock, sensor 920 is an odometer, sensor 921 isa power steering pressure sensor, sensor 922 is a pollution sensor,sensor 923 is a fuel gauge, sensor 924 is a cabin thermometer, sensor925 is a transmission fluid level sensor, sensor 926 is a yaw sensor,sensor 927 is a coolant level sensor, sensor 928 is a transmission fluidturbidity sensor, sensor 929 is brake pressure sensor and sensor 930 isa coolant pressure sensor. Other possible sensors include a temperaturetransducer, a pressure transducer, a liquid level sensor, a flow meter,a position sensor, a velocity sensor, a RPM sensor, a chemical sensorand an angle sensor, angular rate sensor or gyroscope.

[0337] If a distributed group of acceleration sensors or accelerometersare used to permit a determination of the location of a vibrationsource, the same group can, in some cases, also be used to measure thepitch, yaw and/or roll of the vehicle eliminating the need for dedicatedangular rate sensors. In addition, as mentioned above, such a suite ofsensors can also be used to determine the location and severity of avehicle crash and additionally to determine that the vehicle is on theverge of rolling over. Thus, the same suite of accelerometers optimallyperforms a variety of functions including inertial navigation, crashsensing, vehicle diagnostics, roll over sensing etc.

[0338] Consider now some examples. The following is a partial list ofpotential component failures and the sensors from the list on FIG. 8that might provide information to predict the failure of the component:Out of balance tires 901,913,914,915,920,921 Front end out of align-901,913,921,926 ment Tune up required 901,903,910,912,915,917,920,922Oil change needed 903,904,905,911 Motor failure901,902,903,904,905,906,910,912,915,917,922 Low tire pressure901,913,914,915,920,921 Front end looseness 901,913,916,921,926 Coolingsystem failure 903,915,924,927,930 Alternator problems901,902,907,908,915,919,920 Transmission problems901,903,912,915,916,920,925,928 Differential problems 901,912,914 Brakes901,902,914,918,920,926,929 Catalytic converter and 901,902,912,915,922muffler Ignition 901,902,907,908,909,910,912,917,923 Tire wear901,913,914,915,918,920,921,926 Fuel leakage 920,923 Fan belt slippage901,902,903,907,908,912,915,919,920 Alternator deterioration901,902,907,908,915,919 Coolant pump failure 901,902,903,924,927,930Coolant hose failure 901,902,903,927,930 Starter failure901,902,907,908,909,912,915 Dirty air filter 902,903,906,911,912,917,922

[0339] Several interesting facts can be deduced from a review of theabove list. First, all of the failure modes listed can be at leastpartially sensed by multiple sensors. In many cases, some of the sensorsmerely add information to aid in the interpretation of signals receivedfrom other sensors. In today's automobile, there are few if any caseswhere multiple sensors are used to diagnose or predict a problem. Infact, there is virtually no failure prediction undertaken at all.Second, many of the failure modes listed require information from morethan one sensor. Third, information for many of the failure modes listedcannot be obtained by observing one data point in time as is now done bymost vehicle sensors. Usually an analysis of the variation in aparameter as a function of time is necessary. In fact, the associationof data with time to create a temporal pattern for use in diagnosingcomponent failures in automobile is unique to this invention as in thecombination of several such temporal patterns. Fourth, the vibrationmeasuring capability of the airbag crash sensor, or other accelerometer,is useful for most of the cases discussed above yet there is no suchcurrent use of accelerometers. The airbag crash sensor is used only todetect crashes of the vehicle. Fifth, the second most used sensor in theabove list, a microphone, does not currently appear on any automobilesyet sound is the signal most often used by vehicle operators andmechanics to diagnose vehicle problems. Another sensor that is listedabove which also does not currently appear on automobiles is a pollutionsensor. This is typically a chemical sensor mounted in the exhaustsystem for detecting emissions from the vehicle. It is expected thatthis and other chemical sensors will be used more in the future.

[0340] In addition, from the foregoing depiction of different sensorswhich receive signals from a plurality of components, it is possible fora single sensor to receive and output signals from a plurality ofcomponents which are then analyzed by the processor to determine if anyone of the components for which the received signals were obtained bythat sensor is operating in an abnormal state. Likewise, it is alsopossible to provide for a multiplicity of sensors each receiving adifferent signal related to a specific component which are then analyzedby the processor to determine if that component is operating in anabnormal state. Note that neural networks can simultaneously analyzedata from multiple sensors of the same type or different types.

[0341] The discussion above has centered on notifying the vehicleoperator of a pending problem with a vehicle component. Today, there isgreat competition in the automobile marketplace and the manufacturersand dealers who are most responsive to customers are likely to benefitby increased sales both from repeat purchasers and new customers. Thediagnostic module disclosed herein benefits the dealer by making himinstantly aware, through the cellular telephone system, or othercommunication link, coupled to the diagnostic module or system inaccordance with the invention, when a component is likely to fail. Asenvisioned, on some automobiles, when the diagnostic module 870 detectsa potential failure it not only notifies the driver through a display980, but also automatically notifies the dealer through a vehiclecellular phone 990 or other telematics communication link. The dealercan thus contact the vehicle owner and schedule an appointment toundertake the necessary repair at each party's mutual convenience.Contact by the dealer to the vehicle owner can occur as the owner isdriving the vehicle, using a communications device. Thus, the dealercan, contact the driver and informed him of their mutual knowledge ofthe problem and discuss scheduling maintenance to attend to the problem.The customer is pleased since a potential vehicle breakdown has beenavoided and the dealer is pleased since he is likely to perform therepair work. The vehicle manufacturer also benefits by early andaccurate statistics on the failure rate of vehicle components. Thisearly warning system can reduce the cost of a potential recall forcomponents having design defects. It could even have saved lives if sucha system had been in place during the Firestone tire failure problemmentioned above. The vehicle manufacturer will thus be guided towardproducing higher quality vehicles thus improving his competitiveness.Finally, experience with this system will actually lead to a reductionin the number of sensors on the vehicle since only those sensors thatare successful in predicting failures will be necessary.

[0342] For most cases, it is sufficient to notify a driver that acomponent is about to fail through a warning display. In some criticalcases, action beyond warning the driver may be required. If, forexample, the diagnostic module detected that the alternator wasbeginning to fail, in addition to warning the driver of thiseventuality, the module could send a signal to another vehicle system toturn off all non-essential devices which use electricity therebyconserving electrical energy and maximizing the time and distance thatthe vehicle can travel before exhausting the energy in the battery.Additionally, this system can be coupled to a system such as OnStar*) ora vehicle route guidance system, and the driver can be guided to thenearest open repair facility or a facility of his or her choice.

[0343] In the discussion above, the diagnostic module of this inventionassumes that a vehicle data bus exists which is used by all of therelevant sensors on the vehicle. Most vehicles today do not have a databus although it is widely believed that most vehicles will have one inthe near future. Naturally, the relevant signals can be transmitted tothe diagnostic module through a variety of coupling means other thanthrough a data bus and this invention is not limited to vehicles havinga data bus. For example, the data can be sent wirelessly to thediagnostic module using the Bluetooth™ specification. In some cases,even the sensors do not have to be wired and can obtain their power viaRF from the interrogator as is well known in the RFID -radio frequencyidentification (either silicon or surface acoustic wave (SAW) based))field. Alternately an inductive or capacitive power transfer system canbe used.

[0344] As can be appreciated from the above discussion, the inventiondescribed herein brings several new improvements to automobilesincluding, but not limited to, the use of pattern recognitiontechnologies to diagnose potential vehicle component failures, the useof trainable systems thereby eliminating the need of complex andextensive programming, the simultaneous use of multiple sensors tomonitor a particular component, the use of a single sensor to monitorthe operation of many vehicle components, the monitoring of vehiclecomponents which have no dedicated sensors, and the notification of boththe driver and possibly an outside entity of a potential componentfailure in time so that the failure can be averted and vehiclebreakdowns substantially eliminated. Additionally, improvements to thevehicle stability, crash avoidance, crash anticipation and occupantprotection are available.

[0345] To implement a component diagnostic system for diagnosing thecomponent utilizing a plurality of sensors not directly associated withthe component, i.e., independent of the component, a series of tests areconducted. For each test, the signals received from the sensors areinput into a pattern recognition training algorithm with an indicationof whether the component is operating normally or abnormally (thecomponent being intentionally altered to provide for abnormaloperation). The data from the test are used to generate the patternrecognition algorithm, e.g., neural network, so that in use, the datafrom the sensors is input into the algorithm and the algorithm providesan indication of abnormal or normal operation of the component. Also, toprovide a more versatile diagnostic module for use in conjunction withdiagnosing abnormal operation of multiple components, tests may beconducted in which each component is operated abnormally while the othercomponents are operating normally, as well as tests in which two or morecomponents are operating abnormally. In this manner, the diagnosticmodule may be able to determine based on one set of signals from thesensors during use that either a single component or multiple componentsare operating abnormally.

[0346] Furthermore, the pattern recognition algorithm may be trainedbased on patterns within the signals from the sensors. Thus, by means ofa single sensor, it would be possible to determine whether one or morecomponents are operating abnormally. To obtain such a patternrecognition algorithm, tests are conducted using a single sensor, suchas a microphone, and causing abnormal operation of one or morecomponents, each component operating abnormally while the othercomponents operate normally and multiple components operatingabnormally. In this manner, in use, the pattern recognition algorithmmay analyze a signal from a single sensor and determine abnormaloperation of one or more components. Note that in some cases,simulations can be used to analytically generate the relevant data.

[0347] The invention is also particularly useful in light of theforeseeable implementation of smart highways. Smart highways will resultin vehicles traveling down highways under partial or complete control ofan automatic system, i.e., not being controlled by the driver. Theon-board diagnostic system will thus be able to determine failure of acomponent prior to or upon failure thereof and inform the vehicle'sguidance system to cause the vehicle to move out of the stream oftraffic, i.e., onto a shoulder of the highway, in a safe and orderlymanner. Moreover, the diagnostic system may be controlled or programmedto prevent the movement of the disabled vehicle back into the stream oftraffic until the repair of the component is satisfactorily completed.

[0348] In a method in accordance with this embodiment, the operation ofthe component would be monitored and if abnormal operation of thecomponent is detected, e.g., by any of the methods and apparatusdisclosed herein (although other component failure systems may of coursebe used in this implementation), the guidance system of the vehiclewhich controls the movement of the vehicle would be notified, e.g., viaa signal from the diagnostic module to the guidance system, and theguidance system would be programmed to move the vehicle out of thestream of traffic, or off of the restricted roadway, possibly to aservice station or dealer, upon reception of the particular signal fromthe diagnostic module. The automatic guidance systems for vehiclestraveling on highways may be any existing system or system beingdeveloped, such as one based on satellite positioning techniques orground-based positioning techniques. Since the guidance system may beprogrammed to ascertain the vehicle's position on the highway, it candetermine the vehicle's current position, the nearest location out ofthe stream of traffic, or off of the restricted roadway, such as anappropriate shoulder or exit to which the vehicle may be moved, and thepath of movement of the vehicle from the current position to thelocation out of the stream of traffic, or off of the restricted roadway.The vehicle may thus be moved along this path under the control of theautomatic guidance system. In the alternative, the path may be displayedto a driver and the driver can follow the path, i.e., manually controlthe vehicle. The diagnostic module and/or guidance system may bedesigned to prevent re-entry of the vehicle into the stream of traffic,or off of the restricted roadway, until the abnormal operation of thecomponent is satisfactorily addressed.

[0349]FIG. 9 is a flow chart of some of the methods for directing avehicle off of a roadway if a component is operating abnormally. Thecomponent's operation is monitored at 440 and a determination is made at442 whether its operation is abnormal. If not, the operation of thecomponent is monitored further. If the operation of the component isabnormal, the vehicle can be directed off the roadway at 444. Moreparticularly, this can be accomplished by generating a signal indicatingthe abnormal operation of the component at 446, directing this signal toa guidance system in the vehicle at 448 that guides movement of thevehicle off of the roadway at 450. Also, if the component is operatingabnormally, the current position of the vehicle and the location of asite off of the roadway can be determined at 452, e.g., usingsatellite-based or ground-based location determining techniques, a pathfrom the current location to the off-roadway location determined at 454and then the vehicle directed along this path at 456. Periodically, adetermination is made at 458 whether the component's abnormality hasbeen satisfactorily addressed and/or corrected and if so, the vehiclecan re-enter the roadway and operation of the component begins again. Ifnot, the re-entry of the vehicle onto the roadway is prevented at 460.

[0350]FIG. 10 schematically shows the basic components for performingthis method, i.e., a component operation monitoring system 462 (such asdescribed above), an optional satellite-based or ground-basedpositioning system 464 and a vehicle guidance system 466.

[0351]FIG. 11 illustrates the placement of a variety of sensors,primarily accelerometers and/or gyroscopes, which can be used todiagnose the state of the vehicle itself. Sensor 202 can be located inthe headliner or attached to the vehicle roof above the side door.Typically, there can be two such sensors one on either side of thevehicle. Sensor 203 is shown in a typical mounting location midwaybetween the sides of the vehicle attached to or near the vehicle roofabove the rear window. Sensor 206 is shown in a typical mountinglocation in the vehicle trunk adjacent the rear of the vehicle. Eitherone, two or three such sensors can be used depending on the application.If three such sensors are use one would be adjacent each side of vehicleand one in the center. Sensor 204 is shown in a typical mountinglocation in the vehicle door and sensor 205 is shown in a typicalmounting location on the sill or floor below the door. Sensor 207, whichcan be also multiple sensors, is shown in a typical mounting locationforward in the crush zone of the vehicle. Finally, sensor 208 canmeasure the acceleration of the firewall or instrument panel and islocated thereon generally midway between the two sides of the vehicle.If three such sensors are used, one would be adjacent each vehicle sideand one in the center.

[0352] In general, sensors 202-208 provide a measurement of the state ofthe vehicle, such as its velocity, acceleration, angular orientation ortemperature, or a state of the location at which the sensor is mounted.Thus, measurements related to the state of the sensor would includemeasurements of the acceleration of the sensor, measurements of thetemperature of the mounting location as well as changes in the state ofthe sensor and rates of changes of the state of the sensor. As such, anydescribed use or function of the sensors 202-208 above is merelyexemplary and is not intended to limit the form of the sensor or itsfunction.

[0353] Each of the sensors 202-208 may be single axis, double axis ortriaxial accelerometers and/or gyroscopes typically of the MEMS type.These sensors 202-208 can either be wired to the central control moduleor processor directly wherein they would receive power and transmitinformation, or they could be connected onto the vehicle bus or, in somecases, using RFID, SAW or similar technology, the sensors can bewireless and would receive their power through RF from one or moreinterrogators located in the vehicle. In this case, the interrogatorscan be connected either to the vehicle bus or directly to controlmodule. Alternately, an inductive or capacitive power and informationtransfer system can be used.

[0354] One particular implementation will now be described. In thiscase, each of the sensors 202-208 is a single or dual axisaccelerometer. They are made using silicon micromachined technology suchas disclosed in U.S. Pat. Nos. 5,121,180 and 5,894,090. These are onlyrepresentative patents of these devices and there exist more than 100other relevant U.S. patents describing this technology. Commerciallyavailable MEMS gyroscopes such as from Systron Doner have accuracies ofapproximately one degree per second. In contrast, optical gyroscopestypically have accuracies of approximately one degree per hour.Unfortunately, the optical gyroscopes arc prohibitively expensive forautomotive applications. On the other hand, typical MEMS gyroscopes arenot sufficiently accurate for many control applications.

[0355] The angular rate function can be obtained through placingaccelerometers at two separated, non-co-located points in a vehicle andusing the differential acceleration to obtain an indication of angularmotion and angular acceleration. From the variety of accelerometersshown on FIG. 11, it can be appreciated that not only will allaccelerations of key parts of the vehicle be determined, but the pitch,yaw and roll angular rates can also be determined based on the accuracyof the accelerometers. By this method, low cost systems can be developedwhich, although not as accurate as the optical gyroscopes, areconsiderably more accurate than conventional MEMS gyroscopes.Alternately, it has been found that from a single package containing upto three low cost MEMS gyroscopes and three low cost MEMSaccelerometers, when carefully calibrated, an accurate inertialmeasurement unit (IMU) can be constructed that performs as well as unitscosting a great deal more. Such a package is sold by CrossbowTechnology, Inc. 41 Daggett Dr., San Jose, Calif. 95134. If this IMU iscombined with a GPS system and sometimes other vehicle sensor inputsusing a Kalman filter, accuracy approaching that of expensive militaryunits can be achieved.

[0356] Instead of using two accelerometers at separate locations on thevehicle, a single conformal MEMS-IDT gyroscope may be used. Such aconformal MEMS-IDT gyroscope is described in a paper by V. K. Karadan,Conformal MEMS-IDT Gyroscopes and Their Comparison With Fiber OpticGyro, incorporated in its entirety herein. The MEMS-IDT gyroscope isbased on the principle of surface acoustic wave (SAW) standing waves ona piezoelectric substrate. A surface acoustic wave resonator is used tocreate standing waves inside a cavity and the particles at theanti-nodes of the standing waves experience large amplitude ofvibrations, which serves as the reference vibrating motion for thegyroscope. Arrays of metallic dots are positioned at the anti-nodelocations so that the effect of Coriolis force due to rotation willacoustically amplify the magnitude of the waves. Unlike other MEMSgyroscopes, the MEMS-IDT gyroscope has a planar configuration with nosuspended resonating mechanical structures. Other SAW-based gyroscopesare also now under development.

[0357] The system of FIG. 11 using dual axis accelerometers, or the IMUKalman filter system, therefore provides a complete diagnostic system ofthe vehicle itself and its dynamic motion. Such a system is far moreaccurate than any system currently available in the automotive market.This system provides very accurate crash discrimination since the exactlocation of the crash can be determined and, coupled with a knowledge ofthe force deflection characteristics of the vehicle at the accidentimpact site, an accurate determination of the crash severity and thusthe need for occupant restraint deployment can be made. Similarly, thetendency of a vehicle to roll over can be predicted in advance andsignals sent to the vehicle steering, braking and throttle systems toattempt to ameliorate the rollover situation or prevent it. In the eventthat it cannot be prevented, the deployment side curtain airbags can beinitiated in a timely manner.

[0358] Similarly, the tendency of the vehicle to the slide or skid canbe considerably more accurately determined and again the steering,braking and throttle systems commanded to minimize the unstable vehiclebehavior.

[0359] Thus, through the sample deployment of inexpensive accelerometersat a variety of locations in the vehicle, or the IMU Kalman filtersystem significant improvements are made in the vehicle stabilitycontrol, crash sensing, rollover sensing, and resulting occupantprotection technologies.

[0360] Finally, as mentioned above, the combination of the outputs fromthese accelerometer sensors and the output of strain gage weight sensorsin a vehicle seat, or in or on a support structure of the seat, can beused to make an accurate assessment of the occupancy of the seat anddifferentiate between animate and inanimate occupants as well asdetermining where in the seat the occupants are sitting. This can bedone by observing the acceleration signals from the sensors of FIG. 11and simultaneously the dynamic strain gage measurements from seatmounted strain gages. The accelerometers provide the input function tothe seat and the strain gages measure the reaction of the occupying itemto the vehicle acceleration and thereby provide a method of determiningdynamically the mass of the occupying item and its location. This isparticularly important during occupant position sensing during a crashevent. By combining the outputs of the accelerometers and the straingages and appropriately processing the same, the mass and weight of anobject occupying the seat can be determined as well as the gross motionof such an object so that an assessment can be made as to whether theobject is a life form such as a human being.

[0361] For this embodiment, sensor 209 represents one or more straingage weight sensors mounted on the seat or in connection with the seator its support structure. Suitable mounting locations and forms ofweight sensors are discussed in the current assignee's U.S. patentapplication Ser. No. 09/193,209 and contemplated for use in thisinvention as well. The mass or weight of the occupying item of the seatcan thus be measured based on the dynamic measurement of the straingages with optional consideration of the measurements of accelerometerson the vehicle, which are represented by any of sensors 202-208.

[0362]FIG. 12 shows a schematic of the integration of the occupantsensing with a telematics link and the vehicle diagnosis with atelematics link. As envisioned, the occupant sensing system 1000includes those components which determine the presence, position, healthstate, and other information relating to the occupants, for example thetransducers discussed above with reference to FIGS. 1-3 and the SAWdevice discussed above with reference to FIG. 4. Information relating tothe occupants includes information as to what the driver is doing,talking on the phone, communicating with OnStar® or other routeguidance, listening to the radio, sleeping, drunk, drugged, having aheart attack The occupant sensing system may also be any of thosesystems and apparatus described in any of the current assignee'sabove-referenced patents and patent applications incorporated byreference herein, or any other comparable occupant sensing system whichperforms any or all of the same functions as they relate to occupantsensing. Examples of sensors which might be installed on a vehicle andconstitute the occupant sensing system include heartbeat sensors, motionsensors, weight sensors, microphones and optical sensors.

[0363] A crash sensor 1002 is provided and determines when the vehicleexperiences a crash. Crash sensor 1002 may be any type of crash sensor.

[0364] Vehicle sensors 1004 include sensors which detect the operatingconditions of the vehicle such as those sensors discussed with referenceto FIGS. 4-8 above. Also included are tire sensors such as disclosed inU.S. patent application Ser. No. 10/079,065. Other examples includevelocity and acceleration sensors, and angular and angular rate pitch,roll and yaw sensors. Of particular importance are sensors that tellwhat the car is doing: speed, skidding, sliding, location, communicatingwith other cars or the infrastructure, etc.

[0365] Environment sensors 1006 includes sensors which provide data tothe operating environment of the vehicle, e.g., the inside and outsidetemperatures, the time of day, the location of the sun and lights, thelocations of other vehicles, rain, snow, sleet, visibility (fog),general road condition information, pot holes, ice, snow cover, roadvisibility, assessment of traffic, video pictures of an accident, etc.Possible sensors include optical sensors which obtain images of theenvironment surrounding the vehicle, blind spot detectors which providesdata on the blind spot of the driver, automatic cruise control sensorsthat can provide images of vehicles in front of the host vehicle,various radar devices which provide the position of other vehicles andobjects relative to the subject vehicle.

[0366] The occupant sensing system 1000, crash sensors 1002, vehiclesensors 1004, environment sensors 1006 all are coupled to acommunications device 1008 which may contain a memory unit andappropriate electrical hardware to communicate with all of the sensors,process data from the sensors, and transmit data from the sensors. Thememory unit would be useful to store data from the sensors, updatedperiodically, so that such information could be transmitted at set timeintervals.

[0367] The communications device 308 can be designed to transmitinformation to any number of different types of facilities. For example,the communications device 1008 would be designed to transmit informationto an emergency response facility 1010 in the event of an accidentinvolving the vehicle. The transmission of the information would betriggered by a signal from the crash sensor 1002 that the vehicle wasexperiencing a crash or experienced a crash. The information transmittedwould come from the occupant sensing system 1000 so that the emergencyresponse could be tailored to the status of the occupants. For example,if the vehicle was determined to have ten occupants, multiple ambulancesmight be sent than if the vehicle contained only a single occupant.Also, if the occupants are determined not be breathing, then a higherpriority call with living survivors might receive assistance first. Assuch, the information from the occupant sensing system 1000 would beused to prioritize the duties of the emergency response personnel.

[0368] Information from the vehicle sensors 1004 and environment sensors1006 could also be transmitted to law enforcement authorities 1014 inthe event of an accident so that the cause(s) of the accident could bedetermined. Such information can also include information from theoccupant sensing system 1000, which might reveal that the driver wastalking on the phone, putting on make-up, or another distractingactivity, information from the vehicle sensors 1004 which might reveal aproblem with the vehicle, and information from the environment sensors1006 which might reveal the existence of slippery roads, dense fog andthe like.

[0369] Information from the occupant sensing system 1000, vehiclesensors 1004 and environment sensors 1006 could also be transmitted tothe vehicle manufacturer 1016 in the event of an accident so that adetermination can be made as to whether failure of a component of thevehicle causes or contributed to the cause of the accident. For example,the vehicle sensors might determine that the tire pressure was too lowso that advice can be disseminated to avoid maintaining the tirepressure too low in order to avoid an accident. Information from thevehicle sensors 1004 relating to component failure could be transmittedto a dealer/repair facility 1012 which could schedule maintenance tocorrect the problem.

[0370] The communications device 1008 could be designed to transmitparticular information to each site, i.e., only information important tobe considered by the personnel at that site. For example, the emergencyresponse personnel have no need for the fact that the tire pressure wastoo low but such information is important to the law enforcementauthorities 1014 (for the possible purpose of issuing a recall of thetire and/or vehicle) and the vehicle manufacturer 1016.

[0371] The communication device can be a cellular phone, OnStar® orother subscriber-based telematics system, a peer-to-peer vehiclecommunication system that eventually communicates to the infrastructureand then, perhaps, to the Internet with email to the dealer,manufacturer, vehicle owner, law enforcement authorities or others. Itcan also be a vehicle to LEO or Geostationary satellite system such asSkyBytes which can then forward the information to the appropriatefacility either directly or through the Internet.

[0372] The communication may need to be secret so as not to violate theprivacy of the occupants and thus encrypted communication may in manycases be required. Other innovations described herein include thetransmission of any video data from a vehicle to another vehicle or to afacility remote from the vehicle by any means such as a telematicscommunication system such as OnStar®, a cellular phone system, acommunication via GEO, geocentric or other satellite system and anycommunication that communicates the results of a pattern recognitionsystem analysis. Also, any communication from a vehicle that combinessensor information with location information.

[0373] When optical sensors are provided as part of the occupant sensingsystem 1000, video conferencing becomes a possibility, whether or notthe vehicle experiences a crash. That is, the occupants of the vehiclecan engage in a video conference with people at another location 1018via establishment of a communications channel by the communicationsdevice 1008.

[0374] The vehicle diagnostic system described above using a telematicslink can transmit information from any type of sensors on the vehicle.

[0375] In one particular use of the invention, a wireless sensing andcommunication system is provided whereby the information or dataobtained through processing of input from sensors of the wirelesssensing and communication system is further transmitted for reception bya remote facility. Thus, in such a construction, there is anintra-vehicle communications between the sensors on the vehicle and aprocessing system (control module, computer or the like) and remotecommunications between the same or a coupled processing system (controlmodule, computer or the like). The electronic components for theintra-vehicle communication may be designed to transmit and receivesignals over short distances whereas the electronic components whichenable remote communications should be designed to transmit and receivesignals over relatively long distances.

[0376] The wireless sensing and communication system includes sensorsthat are located on the vehicle or in the vicinity of the vehicle andwhich provide information which is transmitted to one or moreinterrogators in the vehicle by wireless radio frequency means, usingwireless radio frequency transmission technology. In some cases, thepower to operate a particular sensor is supplied by the interrogatorwhile in other cases, the sensor is independently connected to either abattery, generator, vehicle power source or some source of powerexternal to the vehicle.

[0377] The sensors for a system installed in a vehicle would likelyinclude tire pressure, temperature and acceleration monitoring sensors,weight or load measuring sensors, switches, temperature, acceleration,angular position, angular rate, angular acceleration, proximity,rollover, occupant presence, humidity, presence of fluids or gases,strain, road condition and friction, chemical sensors and other similarsensors providing information to a vehicle system, vehicle operator orexternal site. The sensors can provide information about the vehicle andits interior or exterior environment, about individual components,systems, vehicle occupants, subsystems, or about the roadway, ambientatmosphere, travel conditions and external objects.

[0378] The system can use one or more interrogators each having one ormore antennas that transmit radio frequency energy to the sensors andreceive modulated radio frequency signals from the sensors containingsensor and/or identification information. One interrogator can be usedfor sensing multiple switches or other devices. For example, aninterrogator may transmit a chirp form of energy at 905 MHz to 925 MHzto a variety of sensors located within or in the vicinity of thevehicle. These sensors may be of the RFID electronic type or of thesurface acoustic wave (SAW) type. In the electronic type, informationcan be returned immediately to the interrogator in the form of amodulated RF signal. In the case of SAW devices, the information can bereturned after a delay. Naturally, one sensor can respond in both theelectronic and SAW delayed modes.

[0379] When multiple sensors are interrogated using the same technology,the returned signals from the various sensors can be time, code, spaceor frequency multiplexed. For example, for the case of the SAWtechnology, each sensor can be provided with a different delay.Alternately, each sensor can be designed to respond only to a singlefrequency or several frequencies. The radio frequency can be amplitudeor frequency modulated. Space multiplexing can be achieved through theuse of two or more antennas and correlating the received signals toisolate signals based on direction.

[0380] In many cases, the sensors will respond with an identificationsignal followed by or preceded by information relating to the sensedvalue, state and/or property. In the case of a SAW-based switch, forexample, the returned signal may indicate that the switch is either onor off or, in some cases, an intermediate state can be providedsignifying that a light should be dimmed, rather than or on or off, forexample.

[0381] Great economies are achieved by using a single interrogator oreven a small number of interrogators to interrogate many types ofdevices. For example, a single interrogator may monitor tire pressureand temperature, the weight of an occupying item of the seat, theposition of the seat and seatback, as well as a variety of switchescontrolling windows, door locks, seat position, etc. in a vehicle. Suchan interrogator may use one or multiple antennas and when multipleantennas are used, may switch between the antennas depending on what isbeing monitored.

[0382] More particularly, the tire monitoring system of this inventionactually comprises three separate systems corresponding to three stagesof product evolution. Generation 1 is a tire valve cap that providesinformation as to the pressure within the tire as described below.Generation 2 requires the replacement of the tire valve stem, or theaddition of a new stem-like device, with a new valve stem that alsomeasures temperature and pressure within the tire or it may be a devicethat attaches to the vehicle wheel rim. Generation 3 is a product thatis attached to the inside of the tire adjacent the tread and provides ameasure of the diameter of the footprint between the tire and the road,the tire pressure and temperature, indications of tire wear and, in somecases, the coefficient of friction between the tire and the road.

[0383] Surface acoustic wave technology permits the measurement of manyphysical and chemical parameters without the requirement of local poweror energy. Rather, the energy to run devices can be obtained from radiofrequency electromagnetic waves. These waves excite an antenna that iscoupled to the SAW device. Through various means, the properties of theacoustic waves on the surface of the SAW device are modified as afunction of the variable to be measured. The SAW device belongs to thefield of microelectromechanical systems (MEMS) and can be produced inhigh-volume at low cost.

[0384] For the generation 1 system, a valve cap contains a SAW materialat the end of the valve cap, which may be polymer covered. This devicesenses the absolute pressure in the valve cap. Upon attaching the valvecap to the valve stem, a depressing member gradually depresses the valvepermitting the air pressure inside the tire to communicate with a smallvolume inside the valve cap. As the valve cap is screwed onto the valvestem, a seal prevents the escape of air to the atmosphere. The SAWdevice is electrically connected to the valve cap, which is alsoelectrically connected to the valve stem that acts as an antenna fortransmitting and receiving radio frequency waves. An interrogatorlocated within 20 feet of the tire periodically transmits radio wavesthat power the SAW device. The SAW device measures the absolute pressurein the valve cap that is equal to the pressure in the tire. U.S. Pat.Nos. 5,641,902, 5,819,779 and 4,103,549 illustrate a valve cap pressuresensor where a visual output is provided. Other related prior artincludes U.S. Pat. No. 4,545,246.

[0385] The generation 2 system permits the measurement of both the tirepressure and tire temperature. In this case, the tire valve stem isremoved and replaced with a new tire valve stem that contains a SAWdevice attached at the bottom of the valve stem. This device actuallycontains two SAW devices, one for measuring temperature and the secondfor measuring pressure through a novel technology discussed below. Thissecond generation device therefore permits the measurement of both thepressure and the temperature inside the tire. Alternately, this devicecan be mounted inside the tire, attached to the rim or attached toanother suitable location. An external pressure sensor is mounted in theinterrogator to measure the pressure of the atmosphere to compensate foraltitude and/or barometric changes.

[0386] The generation 3 device contains a pressure and temperaturesensor, as in the case of the generation 2 device, but additionallycontains one or more accelerometers which measure at least one componentof the acceleration of the vehicle tire tread adjacent the device. Thisacceleration varies in a known manner as the device travels in anapproximate circle attached to the wheel. This device is capable ofdetermining when the tread adjacent the device is in contact with roadsurface. It is also able to measure the coefficient of friction betweenthe tire and the road surface. In this manner, it is capable ofmeasuring the length of time that this tread portion is in contact withthe road and thereby provides a measure of the diameter of the tirefootprint on the road. A technical discussion of the operating principleof a tire inflation and load detector based on flat area detectionfollows:

[0387] When tires are inflated and not in contact with the ground, theinternal pressure is balanced by the circumferential tension in thefibers of the shell. Static equilibrium demands that tension is equal tothe radius of curvature multiplied by the difference between theinternal and the external gas pressure. Tires support the weight of theautomobile by changing the curvature of the part of the shell thattouches the ground. The relation mentioned above is still valid. In thepart of the shell that gets flattened, the radius of curvature increaseswhile the tension in the tire structure stays the same. Therefore, thedifference between the external and internal pressures becomes small tocompensate for the growth of the radius. If the shell were perfectlyflexible, the tire contact with the ground would develop into a flatspot with an area equal to the load divided by the pressure.

[0388] A tire operating at correct values of load and pressure has aprecise signature in terms of variation of the radius of curvature inthe loaded zone. More flattening indicates under-inflation oroverloading, while less flattening indicates over-inflation orunder-loading. Note that tire loading has essentially no effect oninternal pressure.

[0389] From the above, one can conclude that monitoring the curvature ofthe tire as it rotates can provide a good indication of its operationalstate. A sensor mounted inside the tire at its largest diameter canaccomplish this measurement. Preferably, the sensor would measuremechanical strain. However, a sensor measuring acceleration in any oneaxis could also serve the purpose.

[0390] In the case of the strain measurement, the sensor would indicatea constant strain as it spans the arc over which the tire is not incontact with the ground, and a pattern of increased stretch during thearc of close proximity with the ground. A simple ratio of the times ofduration of these two states would provide a good indication ofinflation, but more complex algorithms could be employed, where thevalues and the shape of the period of increased strain are utilized.

[0391] In the case of acceleration measurement, the system would utilizethe fact that the part of the tire in contact with the ground possesseszero velocity for a finite period of time, while the rest of the tire isaccelerating and decelerating in a cyclic fashion. The resultingacceleration profiles in the circumferential axis or the radial axispresent a characteristic near-zero portion, the length of which, whenrelated to the rest of the rotation, is a result of the state of tireinflation.

[0392] As an indicator of tire health, the measurement of strain on thelargest inside diameter of the tire is believed to be superior to themeasurement of stress, such as inflation pressure, because, the tirecould be deforming, as it ages or otherwise progresses toward failure,without any changes in inflation pressure. Radial strain could also bemeasured on the inside of the tire sidewall thus indicating the degreeof flexure that the tire undergoes.

[0393] The accelerometer approach has the advantage of giving asignature from which a harmonic analysis of once-per-revolutiondisturbances could indicate developing problems such as hernias, flatspots, loss of part of the tread, sticking of foreign bodies to thetread, etc.

[0394] As a bonus, both of the above-mentioned sensors give clearonce-per-revolution signals for each tire that could be used as inputsfor speedometers, odometers, differential slip indicators, tire wearindicators, etc.

[0395] Tires can fail for a variety of reasons including low pressure,high temperature, delamination of the tread, excessive flexing of thesidewall, and wear (see, e.g., Summary Root Cause AnalysisBridgestone/Firestone, Inc.”http://www.bridgestone-firestone.com/homeimgs/rootcause.htm, PrintedMarch, 2001). Most tire failures can be predicted based on tire pressurealone and the TREAD Act thus addresses the monitoring of tire pressure.However, some failures, such as the Firestone tire failures, can resultfrom substandard materials especially those that are in contact with asteel-reinforcing belt. If the rubber adjacent the steel belt begins tomove relative to the belt, then heat will be generated and thetemperature of the tire will rise until the tire fails catastrophically.This can happen even in properly inflated tires.

[0396] Finally, tires can fail due to excessive vehicle loading andexcessive sidewall flexing even if the tire is properly inflated. Thiscan happen if the vehicle is overloaded or if the wrong size tire hasbeen mounted on the vehicle. In most cases, the tire temperature willrise as a result of this additional flexing, however, this is not alwaysthe case, and it may even occur too late. Therefore, the device whichmeasures the diameter of the tire footprint on the road is a superiormethod of measuring excessive loading of the tire.

[0397] Generation 1 devices monitor pressure only while generation 2devices also monitor the temperature and therefore will provide awarning of imminent tire failure more often than through monitoringpressure alone. Generation 3 devices will give an indication that thevehicle is overloaded before either a pressure or temperature monitoringsystem can respond. The generation 3 system can also be augmented tomeasure the vibration signature of the tire and thereby detect when atire has worn to the point that the steel belt is contacting the road.In this manner, the generation 3 system also provides an indication of aworn out tire and, as will be discussed below, an indication of the roadcoefficient of friction.

[0398] Each of these devices communicates to an interrogator withpressure, temperature, and acceleration as appropriate In none of thesegenerational devices is a battery mounted within the vehicle tirerequired, although in some cases a generator can be used. In most cases,the SAW devices will optionally provide an identification numbercorresponding to the device to permit the interrogator to separate onetire from another.

[0399] Key advantages of the tire monitoring system disclosed hereinover most of the currently known prior art are:

[0400] very small size and insignificant weight eliminating the need forwheel counterbalance,

[0401] cost competitive for tire monitoring only, significant costadvantage when systems are combined,

[0402] exceeds customers' price targets,

[0403] high update rate,

[0404] self-diagnostic,

[0405] automatic wheel identification,

[0406] no batteries required—powerless,

[0407] no wires required—wireless.

[0408] SAW devices have been used for sensing many parameters includingdevices for chemical sensing and materials characterization in both thegas and liquid phase. They also are used for measuring pressure, strain,temperature, acceleration, angular rate and other physical states of theenvironment.

[0409] The monitoring of temperature and or pressure of a tire can takeplace infrequently. It is adequate to check the pressure and temperatureof vehicle tires once every ten seconds to once per minute. To utilizethe centralized interrogator of this invention, the tire monitoringsystem would preferably use SAW technology and the device could belocated in the valve stem, wheel, tire side wall, tire tread, or otherappropriate location with access to the internal tire pressure of thetires. A preferred system is based on a SAW technology discussed above.

[0410] At periodic intervals, such as once every minute, theinterrogator sends a radio frequency signal at a frequency such as 905MHz to which the tire monitor sensors have been sensitized. Whenreceiving this signal, the tire monitor sensors (of which there are fivein a typical configuration) respond with a signal providing an optionalidentification number, temperature and pressure data. In oneimplementation, the interrogator would use multiple, typically two orfour, antennas which are spaced apart. By comparing the time of thereturned signals from the tires to the antennas, the location of each ofthe senders can be approximately determined. That is, the antennas canbe so located that each tire is a different distance from each antennaand by comparing the return time of the signals sensed by the antennas,the location of each tire can be determined and associated with thereturned information. If at least three antennas are used, then returnsfrom adjacent vehicles can be eliminated.

[0411] An identification number can accompany each transmission fromeach tire sensor and can also be used to validate that the transmittingsensor is in fact located on the subject vehicle. In traffic situations,it is possible to obtain a signal from the tire of an adjacent vehicle.This would immediately show up as a return from more than five vehicletires and the system would recognize that a fault had occurred. Thesixth return can be easily eliminated, however, since it could containan identification number that is different from those that haveheretofore been returned frequently to the vehicle system or based on acomparison of the signals sensed by the different antennas. Thus, whenthe vehicle tire is changed or tires are rotated, the system willvalidate a particular return signal as originating from thetire-monitoring sensor located on the subject vehicle.

[0412] This same concept is also applicable for other vehicle-mountedsensors. This permits a plug and play scenario whereby sensors can beadded to, changed, or removed from a vehicle and the interrogationsystem will automatically adjust. The system will know the type ofsensor based on the identification number, frequency, delay and/or itslocation on the vehicle. For example, a tire monitor could have adifferent code in the identification number from a switch orweight-monitoring device. This also permits new kinds of sensors to beretroactively installed on a vehicle. If a totally new type of thesensor is mounted to the vehicle, the system software would have to beupdated to recognize and know what to do with the information from thenew sensor type. By this method, the configuration and quantity ofsensing systems on a vehicle can be easily changed and the systeminterrogating these sensors need only be updated with software upgradeswhich could occur automatically over the Internet.

[0413] Preferred tire-monitoring sensors for use with this invention usethe surface acoustic wave (SAW) technology. A radio frequencyinterrogating signal is sent to all of the tire gages simultaneously andthe received signal at each tire gage is sensed using an antenna. Theantenna is connected to the IDT transducer that converts the electricalwave to an acoustic wave that travels on the surface of a material suchas lithium niobate, or other piezoelectric material such as zinc oxide,Langasite or the polymer polyvinylidene fluoride (PVDF). During itstravel on the surface of the piezoelectric material, either the timedelay, resonant frequency, amplitude, or phase of the signal (or evenpossibly combinations thereof) is modified based on the temperatureand/or pressure in the tire. This modified wave is sensed by one or moreIDT transducers and converted back to a radio frequency wave that isused to excite an antenna for re-broadcasting the wave back tointerrogator. The interrogator receives the wave at a time delay afterthe original transmission that is determined by the geometry of the SAWtransducer and decodes this signal to determine the temperature and/orpressure in the subject tire. By using slightly different geometries foreach of the tire monitors, slightly different delays can be achieved andrandomized so that the probability of two sensors having the same delayis small. The interrogator transfers the decoded information to acentral processor that then determines whether the temperature and/orpressure of each of the tires exceed specifications. If so, a warninglight can be displayed informing the vehicle driver of the condition. Insome cases, this random delay is all that is required to separate thefive tire signals and to identify which tires are on the vehicle andthus ignore responses from adjacent vehicles.

[0414] With an accelerometer mounted in the tire, as is the case for thegeneration 3 system, information is present to diagnose other tireproblems. For example, when the steel belt wears through the rubbertread, it will make a distinctive noise and create a distinctivevibration when it contacts the pavement. This can be sensed by the SAWaccelerometer. The interpretation of various such signals can be doneusing neural network technology. Similar systems are described moredetail in U.S. Pat. No. 5,829,782, incorporated by reference herein. Asthe tread begins to separate from the tire as in the Bridgestone cases,a distinctive vibration is created which can also be sensed by atire-mounted accelerometer.

[0415] As the tire rotates, stresses are created in the rubber treadsurface between the center of the footprint and the edges. If thecoefficient of friction on the pavement is low, these stresses can causethe shape of the footprint to change. The generation 3 system, whichmeasures the circumferential length of the footprint, can therefore alsobe used to measure the friction coefficient between the tire and thepavement.

[0416] Similarly, the same or a different interrogator can be used tomonitor various components of the vehicle's safety system includingoccupant position sensors, vehicle acceleration sensors, vehicle angularposition, velocity and acceleration sensors, related to both frontal,side or rear impacts as well as rollover conditions. The interrogatorcould also be used in conjunction with other detection devices such asweight sensors, temperature sensors, accelerometers which are associatedwith various systems in the vehicle to enable such systems to becontrolled or affected based on the measured state.

[0417] Some specific examples of the use of interrogators and responsivedevices will now be described.

[0418] The antennas used for interrogating the vehicle tire pressuretransducers will be located outside of the vehicle passengercompartment. For many other transducers to be sensed the antennas mustbe located at various positions within passenger compartment. Thisinvention contemplates, therefore, a series of different antennasystems, which can be electronically switched by the interrogatorcircuitry. Alternately, in some cases, all of the antennas can be leftconnected and total transmitted power increased.

[0419] There are several applications for weight or load measuringdevices in a vehicle including the vehicle suspension system and seatweight sensors for use with automobile safety systems. As reported inU.S. Pat. Nos. 4,096,740, 4,623,813, 5,585,571, 5,663,531, 5,821,425 and5,910,647 and International Publication No. WO 00/65320(A1), all ofwhich are incorporated by reference herein to the extent the disclosureof these publications is necessary, SAW devices are appropriatecandidates for such weight measurement systems. In this case, thesurface acoustic way on the lithium niobate, or other piezoelectricmaterial, is modified in delay time, resonant frequency, amplitudeand/or phase based on strain of the member upon which the SAW device ismounted. For example, the conventional bolt that is typically used toconnect the passenger seat to the seat adjustment slide mechanism can bereplaced with a stud which is threaded on both ends. A SAW strain deviceis mounted to the center unthreaded section of the stud and the stud isattached to both the seat and the slide mechanism using appropriatethreaded nuts. Based on the particular geometry of the SAW device used,the stud can result in as little as a 3 mm upward displacement of theseat compared to a normal bolt mounting system. No wires are required toattach the SAW device to the stud. The interrogator transmits a radiofrequency pulse at, for example, 925 MHz that excites antenna on the SAWstrain measuring system. After a delay caused by the time required forthe wave to travel the length of the SAW device, a modified wave isre-transmitted to the interrogator providing an indication of the strainof the stud with the weight of an object occupying the seatcorresponding to the strain. For a seat that is normally bolted to theslide mechanism with four bolts, at least four SAW strain sensors wouldbe used. Since the individual SAW devices are very small, multipledevices can be placed on a stud to provide multiple redundantmeasurements, or permit bending strains to be determined, and/or topermit the stud to be arbitrarily located with at least one SAW devicealways within direct view of the interrogator antenna. In some cases,the bolt or stud will be made on non-conductive material to limit theblockage of the RF signal. In other cases, it will be insulated from theslide (mechanism) and used as an antenna.

[0420] If two longitudinally spaced apart antennas are used to receivethe SAW transmissions from the seat weight sensors, one antenna in frontof the seat and the other behind the seat, then the position of the seatcan be determined eliminating the need for current seat positionsensors. A similar system can be used for other seat and seatbackposition measurements.

[0421] For strain gage weight sensing, the frequency of interrogationwould be considerably higher than that of the tire monitor, for example.However, if the seat is unoccupied then the frequency of interrogationcan be substantially reduced. For an occupied seat, information as tothe identity and/or category and position of an occupying item of theseat can be obtained through the multiple weight sensors described. Forthis reason, and due to the fact that during the pre-crash event theposition of an occupying item of the seat may be changing rapidly,interrogations as frequently as once every 10 milliseconds can bedesirable. This would also enable a distribution of the weight beingapplied to the seat to be obtained which provides an estimation of theposition of the object occupying the seat. Using pattern recognitiontechnology, e.g., a trained neural network, sensor fusion, fuzzy logic,etc., the identification of the object can be ascertained based on thedetermined weight and/or determined weight distribution.

[0422] There are many other methods by which SAW devices can be used todetermine the weight and/or weight distribution of an occupying itemother than the method described above and all such uses of SAW strainsensors for determining the weight and weight distribution of anoccupant are contemplated. For example, SAW devices with appropriatestraps can be used to measure the deflection of the seat cushion top orbottom caused by an occupying item, or if placed on the seat belts, theload on the belts can determined wirelessly and powerlessly. Geometriessimilar to those disclosed in U.S. Pat. No. 6,242,701 (which disclosesmultiple strain gage geometries, the entire disclosure of this patent isincorporated by reference herein to the extent the disclosure isnecessary) using SAW strain-measuring devices can also be constructed,e.g., any of the multiple strain gage geometries shown therein.

[0423] Although a preferred method for using the invention is tointerrogate each of the SAW devices using wireless means, in some casesit may be desirable to supply power to and/or obtain information fromone or more of the devices using wires. As such, the wires would be anoptional feature.

[0424] One advantage of the weight sensors of this invention along withthe geometries disclosed in the '701 patent and herein below, is that inaddition to the axial stress in the seat support, the bending moments inthe structure can be readily determined. For example, if a seat issupported by four “legs”, it is possible to determine the state ofstress, assuming that axial twisting can be ignored, using four straingages on each leg support for a total of 16 such gages. If the seat issupported by three legs, then this can be reduced to 12. Naturally, athree-legged support is preferable than four since with four, the seatsupport is over-determined severely complicating the determination ofthe stress caused by an object on the seat. Even with three supports,stresses can be introduced depending on the nature of the support at theseat rails or other floor-mounted supporting structure. If simplesupports are used that do not introduce bending moments into thestructure, then the number of gages per seat can be reduced to threeproviding a good model of the seat structure is available.Unfortunately, this is usually not the case and most seats have foursupports and the attachments to the vehicle not only introduce bendingmoments into the structure but these moments vary from one position toanother and with temperature. The SAW strain gages of this inventionlend themselves to the placement of multiple gages onto each support asneeded to approximately determine the state of stress and thus theweight of the occupant depending on the particular vehicle application.Furthermore, the wireless nature of these gages greatly simplifies theplacement of such gages at those locations that are most appropriate.

[0425] One additional point should be mentioned. In many cases, thedetermination of the weight of an occupant from the static strain gagereadings yields inaccurate results due to the indeterminate stress statein the support structure. However, the dynamic stresses to a first orderare independent of the residual stress state. Thus, the change in stressthat occurs as a vehicle travels down a roadway caused by dips in theroadway can provide an accurate measurement of the weight of an objectin a seat. This is especially true if an accelerometer is used tomeasure the vertical excitation provided to the seat.

[0426] Some vehicle models provide load leveling and ride controlfunctions that depend on the magnitude and distribution of load carriedby the vehicle suspension. Frequently, wire strain gage technology isused for these functions. That is, the wire strain gages are used tosense the load and/or load distribution of the vehicle on the vehiclesuspension system. Such strain gages can be advantageously replaced withstrain gages based on SAW technology with the significant advantages interms of cost, wireless monitoring, dynamic range, and signal level. Inaddition, SAW strain gage systems can be significantly more accuratethan wire strain gage systems.

[0427] A strain detector in accordance with this invention can convertmechanical strain to variations in electrical 'signal frequency with alarge dynamic range and high accuracy even for very small displacements.The frequency variation is produced through use of a surface acousticwave delay line as the frequency control element of an oscillator. Asurface acoustic wave delay line comprises a transducer deposited on apiezoelectric material such as quartz or lithium niobate which isdisposed so as to be deformed by strain in the member which is to bemonitored. Deformation of the piezoelectric substrate changes thefrequency control characteristics of the surface acoustic wave delayline, thereby changing the frequency of the oscillator. Consequently,the oscillator frequency change is a measure of the strain in the memberbeing monitored and thus the weight applied to the seat. A SAW straintransducer is capable of a degree of accuracy substantially greater thanthat of a conventional resistive strain gage.

[0428] Other applications of weight measuring systems for an automobileinclude measuring the weight of the fuel tank or other containers offluid to determine quantity of fluid contained therein.

[0429] One problem with SAW devices is that if they are designed tooperate at the GHz frequency, the feature sizes become exceeding smalland the devices are difficult to manufacture. On the other hand, if thefrequencies are considerably lower, for example, in the tens ofmegahertz range, then the antenna sizes become excessive. It is alsomore difficult to obtain antenna gain at the lower frequencies. This isalso related to antenna size. One method of solving this problem is totransmit an interrogation signal in the many GHz range which ismodulated at the hundred MHz range. At the SAW transducer, thetransducer is tuned to the modulated frequency. Using a nonlinear devicesuch as a Shocky diode, the modified signal can be mixed with theincoming high frequency signal and re-transmitted through the sameantenna. For this case, the interrogator could continuously broadcastthe carrier frequency.

[0430] In addition to measuring the weight of an occupying item on aseat, the location of the seat and setback can also be determined by theinterrogator. Since the SAW devices inherently create a delayed returnsignal, either that delay must be very accurately known or an alternateapproach is required. One such alternate approach is to use theheterodyne principal described above to cause the antenna to return asignal of a different frequency. By comparing the phases of the sendingand received signal, the distance to the device can be determined. Also,as discussed above, multiple antennas can be used for seat position andseatback position sensing.

[0431] With respect to switches, devices based on RFID technology can beused as switches in a vehicle as described in U.S. Pat. Nos. 6,078,252and 6,144,288, and U.S. provisional patent application Ser. No.60/231,378 all of which are incorporated by reference herein. There aremany ways that it can be accomplished. A switch can be used to connectan antenna to either an RFID electronic device or to an RFID SAW device.This of course requires contacts to the closed by the switch activation.An alternate approach is to use pressure from an occupant's finger, forexample, to alter the properties of the acoustic wave on the SAWmaterial much as in a SAW touch screen. These properties that can bemodified include the amplitude of the acoustic wave, and its phase,and/or the time delay or an external impedance connected to one of theSAW reflectors as disclosed in U.S. Pat. No. 6,084,503, incorporated byreference herein. In this implementation, the SAW transducer can containtwo sections, one which is modified by the occupant and the other whichserves as a reference. A combined signal is sent to the interrogatorthat decodes the signal to determine that the switch has been activated.By any of these technologies, switches can be arbitrarily placed withinthe interior of an automobile, for example, without the need for wires.(The wires would be an optional feature.) Since wires and connectors arethe clause of most warranty repairs in an automobile, not only is thecost of switches substantially reduced but also the reliability of thevehicle electrical system is substantially improved.

[0432] The interrogation of switches can take place with moderatefrequency such as once every 100 milliseconds. Either through the use ofdifferent frequencies or different delays, a large number of switchescan be either time, code, space or frequency multiplexed to permitseparation of the signals obtained by the interrogator.

[0433] Another approach is to attach a variable impedance device acrossone of the reflectors on the SAW device. The impedance can thereforeused to determine the relative reflection from the reflector compared toother reflectors on the SAW device. In this way, the magnitude as wellas the presence of a force exerted by an occupant's finger, for example,can be used to provide a rate sensitivity to the desired function. In analternate design, as shown U.S. Pat. No. 6,144,288, incorporated byreference herein, the switch is used to connect the antenna to the SAWdevice. Of course, in this case the interrogator will not get a returnfrom the SAW switch unless it is depressed.

[0434] Temperature measurement is another field in which SAW technologycan be applied and the invention encompasses several embodiments of SAWtemperature sensors.

[0435] U.S. Pat. No. 4,249,418, incorporated by reference herein, is oneof many examples of prior art SAW temperature sensors. Temperaturesensors are commonly used within vehicles and many more applicationsmight exist if a low cost wireless temperature sensor is available,i.e., the invention. The SAW technology can be used for such temperaturesensing tasks. These tasks include measuring the vehicle coolanttemperature, air temperature within passenger compartment at multiplelocations, seat temperature for use in conjunction with seat warming andcooling systems, outside temperatures and perhaps tire surfacetemperatures to provide early warning to operators of road freezingconditions. One example, is to provide air temperature sensors in thepassenger compartment in the vicinity of ultrasonic transducers used inoccupant sensing systems as described in the current assignee's U.S. PatNo. 5,943,295 (Varga et al.), incorporated by reference herein, sincethe speed of sound in the air varies by approximately 20% from −40° C.to 85° C. The subject matter of this patent is included in the inventionto form a part thereof. Current ultrasonic occupant sensor systems donot measure or compensate for this change in the speed of sound with theeffect of significantly reducing the accuracy of the systems at thetemperature extremes. Through the judicious placement of SAW temperaturesensors in the vehicle, the passenger compartment air temperature can beaccurately estimated and the information provided wirelessly to theultrasonic occupant sensor system thereby permitting corrections to bemade for the change in speed of sound.

[0436] Acceleration sensing is another field in which SAW technology canbe applied and the invention encompasses several embodiments of SAWaccelerometers.

[0437] U.S. Pat. Nos. 4,199,990, 4,306,456 and 4,549,436, all of whichare incorporated by reference herein, are examples of prior art SAWaccelerometers. Most airbag crash sensors for determining whether thevehicle is experiencing a frontal or side impact currently usemicromachined accelerometers. These accelerometers are usually based onthe deflection of a mass which is sensed using either capacitive orpiezoresistive technologies. SAW technology has heretofore not been usedas a vehicle accelerometer or for vehicle crash sensing. Due to theimportance of this function, at least one interrogator could bededicated to this critical function. Acceleration signals from the crashsensors should be reported at least preferably every 100 microseconds.In this case, the dedicated interrogator would send an interrogationpulse to all crash sensor accelerometers every 100 microseconds andreceive staggered acceleration responses from each of the SAWaccelerometers wirelessly. This technology permits the placement ofmultiple low-cost accelerometers at ideal locations for crash sensingincluding inside the vehicle side doors, in the passenger compartmentand in the frontal crush zone. Additionally crash sensors can now belocated in the rear of the vehicle in the crush zone to sense rearimpacts. Since the acceleration data is transmitted wirelessly, concernabout the detachment or cutting of wires from the sensors disappears.One of the main concerns, for example, of placing crash sensors in thevehicle doors where they most appropriately can sense vehicle sideimpacts, is the fear that an impact into the A-pillar of the automobilewould sever the wires from the door-mounted crash sensor before thecrash was sensed. This problem disappears with the current wirelesstechnology of this invention. If two accelerometers are placed at somedistance from each other, the roll rate of the vehicle can be determinedand thus the tendency of the vehicle to rollover can be predicted intime to automatically take corrective action and/or deploy a curtainairbag or other airbag(s).

[0438] Although the sensitivity of measurement is considerably greaterthan that obtained with conventional piezoelectric accelerometers, thefrequency deviation remains low in absolute value. Accordingly, thefrequency drift of thermal origin has to be made as low as possible byselecting a suitable cut of the piezoelectric material. The resultingaccuracy is impressive as presented in U.S. Pat. No. 4,549,436,incorporated by reference herein, which discloses an angularaccelerometer with a dynamic a range of 1 million, temperaturecoefficient of 0.005% /deg F, an accuracy of 1 microradian/sec², a powerconsumption of 1 milliwatt, a drift of 0.01% per year, a volume of 1cc/axis and a frequency response of 0 to 1000 Hz. The subject matter ofthis patent is hereby included in the invention to constitute a part ofthe invention. A similar design can be used for acceleration sensing.

[0439] In a similar manner as the polymer coated SAW device is used tomeasure pressure, a similar device wherein a seismic mass is attached toa SAW device through a polymer interface can be made to senseacceleration. This geometry has a particular advantage for sensingaccelerations below 1 G, which has proved to be very difficult inconventional micromachined accelerometers due to their inability to bothmeasure low accelerations and withstand shocks.

[0440] Gyroscopes are another field in which SAW technology can beapplied and the invention encompasses several embodiments of SAWgyroscopes.

[0441] The SAW technology is particularly applicable for gyroscopes asdescribed in International Publication No. WO 00/79217A2 to Varadan etal. The output of such gyroscopes can be determined with an interrogatorthat is also used for the crash sensor accelerometers, or a dedicatedinterrogator can be used. Gyroscopes having an accuracy of approximately1 degree per second have many applications in a vehicle including skidcontrol and other dynamic stability functions. Additionally, gyroscopesof similar accuracy can be used to sense impending vehicle rolloversituations in time to take corrective action.

[0442] SAW gyroscopes of the type described in WO 00/79217A2 have thecapability of achieving accuracies approaching 3 degrees per hour. Thishigh accuracy permits use of such gyroscopes in an inertial measuringunit (IMU) that can be used with accurate vehicle navigation systems andautonomous vehicle control based on differential GPS corrections. Such asystem is described in the current assignee's U.S. patent applicationSer. No. 09/177,041. Such navigation systems depend on the availabilityof four or more GPS satellites and an accurate differential correctionsignal such as provided by the OmniStar Corporation or NASA or throughthe National Differential GPS system now being deployed. Theavailability of these signals degrades in urban canyon environments,tunnels, and on highways when the vehicle is in the vicinity of largetrucks. For this application, an IMU system should be able to accuratelycontrol the vehicle for perhaps 15 seconds and preferably for up to fiveminutes. An IMU based on SAW technology or the technology of U.S. Pat.No. 4,549,436 discussed above are the best-known devices capable ofproviding sufficient accuracies for this application at a reasonablecost. Other accurate gyroscope technologies such as fiber optic systemsare more accurate but can cost many thousands of dollars. In contrast,in high volume production, an IMU of the required accuracy based on SAWtechnology should cost less than $100.

[0443] Once an IMU of the accuracy described above is available in thevehicle, this same device can be used to provide significantimprovements to vehicle stability control and rollover predictionsystems.

[0444] Keyless entry systems are another field in which SAW technologycan be applied and the invention encompasses several embodiments ofaccess control systems using SAW devices.

[0445] A common use of SAW technology is for access control tobuildings. RFID technology using electronics is also applicable for thispurpose; however, the range of electronic RFID technology is usuallylimited to one meter or less. In contrast, the SAW technology can permitsensing up to about 30 meters. As a keyless entry system, an automobilecan be configured such that the doors unlock as the holder of a cardcontaining the SAW ID system approaches the vehicle and similarly, thevehicle doors can be automatically locked when occupant with the cardtravels beyond a certain distance from the vehicle. When the occupantenters the vehicle, the doors can again automatically lock eitherthrough logic or through a current system wherein doors automaticallylock when the vehicle is placed in gear. An occupant with such a cardwould also not need to have an ignition key. The vehicle would recognizethat the SAW based card was inside vehicle and then permit the vehicleto be started by issuing an oral command if a voice recognition systemis present or by depressing a button, for example, without the need foran ignition key.

[0446] Occupant presence and position sensing is another field in whichSAW technology can be applied and the invention encompasses severalembodiments of SAW occupant presence and/or position sensors.

[0447] Many sensing systems are available for the use to identify andlocate occupants or other objects in a passenger compartment of thevehicle. Such sensors include ultrasonic sensors, chemical sensors (e.g.carbon dioxide), cameras, radar systems, heat sensors, capacitance,magnetic or other field change sensors, etc. Most of these sensorsrequire power to operate and return information to a central processorfor analysis. An ultrasonic sensor, for example, may be mounted in ornear the headliner of the vehicle and periodically it transmits a fewultrasonic waves and receives reflections of these waves from occupyingitems of the passenger seat. Current systems on the market arecontrolled by electronics in a dedicated ECU.

[0448] An alternate method as taught in this invention is to use aninterrogator to send a signal to the headliner-mounted ultrasonic sensorcausing that sensor to transmit and receive ultrasonic waves. The sensorin this case would perform mathematical operations on the received wavesand create a vector of data containing perhaps twenty to forty valuesand transmit that vector wirelessly to the interrogator. By means ofthis system, the ultrasonic sensor need only be connected to the vehiclepower system and the information could be transferred to and from thesensor wirelessly. Such a system significantly reduces the wiringcomplexity especially when there may be multiple such sensorsdistributed in the passenger compartment. Now, only a power wire needsto be attached to the sensor and there does not need to be any directconnection between the sensor and the control module. Naturally, thesame philosophy would apply to radar-based sensors, electromagneticsensors of all kinds including cameras, capacitive or otherelectromagnetic field change sensitive sensors etc. In some cases, thesensor itself can operate on power supplied by the interrogator throughradio frequency transmission. In this case, even the connection to thepower line can be omitted. This principle can be extended to the largenumber of sensors and actuators that are currently in the vehicle wherethe only wires that are needed are those to supply power to the sensorsand actuators and the information is supplied wirelessly.

[0449] Such wireless powerless sensors can also be use, for example, asclose proximity sensors based on measurement of thermal radiation froman occupant. Such sensors can be mounted on any of the surfaces in thepassenger compartment, including the seats, which are likely to receivesuch radiation.

[0450] A significant number of people are suffocated each year inautomobiles due to excessive heat, carbon dioxide, carbon monoxide, orother dangerous fumes. The SAW sensor technology is particularlyapplicable to solving these kinds of problems. The temperaturemeasurement capabilities of SAW transducers have been discussed above.If the surface of a SAW device is covered with a material which capturescarbon dioxide, for example, such that the mass, elastic constants orother property of surface coating changes, the characteristics of thesurface acoustic waves can be modified as described in detail in U.S.Pat. No. 4,637,987 and elsewhere. Once again, an interrogator can sensethe condition of these chemical-sensing sensors without the need tosupply power and connect the sensors with either wireless communicationor through the power wires. If a concentration of carbon monoxide issensed, for example, an alarm can be sounded, the windows opened, and/orthe engine extinguished. Similarly, if the temperature within thepassenger compartment exceeds a certain level, the windows can beautomatically opened a little to permit an exchange of air reducing theinside temperature and thereby perhaps saving the life of an infant orpet left in the vehicle unattended.

[0451] In a similar manner, the coating of the surface wave device cancontain a chemical which is responsive to the presence of alcohol. Inthis case, the vehicle can be prevented from operating when theconcentration of alcohol vapors in the vehicle exceeds some determinedlimit.

[0452] Each year a number of children and animals are killed when theyare locked into a vehicle trunk. Since children and animals emitsignificant amounts of carbon dioxide, a carbon dioxide sensor connectedto the vehicle system wirelessly and powerlessly provides an economicway of detecting the presence of a life form in the trunk. If a lifeform is detected, then a control system can release a trunk lock therebyopening the trunk. Alarms can also be sounded or activated when a lifeform is detected in the trunk.

[0453] Although they will not be discussed in detail, SAW sensorsoperating in the wireless mode can also be used to sense for ice on thewindshield or other exterior surfaces of the vehicle, condensation onthe inside of the windshield or other interior surfaces, rain sensing,heat load sensing and many other automotive sensing functions. They canalso be used to sense outside environmental properties and statesincluding temperature, humidity, etc.

[0454] SAW sensors can be economically used to measure the temperatureand humidity at numerous places both inside and outside of a vehicle.When used to measure humidity inside the vehicle, a source of watervapor can be activated to increase the humanity when desirable and theair conditioning system can be activated to reduce the humidity whennecessary. Temperature and humidity measurements outside of the vehiclecan be an indication of potential road icing problems. Such informationcan be used to provide early warning to a driver of potentiallydangerous conditions. Although the invention described herein is relatedto land vehicles, many of these advances are equally applicable to othervehicles such as boats, airplanes and even, in some cases, homes andbuildings. The invention disclosed herein, therefore, is not limited toautomobiles or other land vehicles.

[0455] Road condition sensing is another field in which SAW technologycan be applied and the invention encompasses several embodiments of SAWroad condition sensors.

[0456] The temperature and moisture content of the surface of a roadwayare critical parameters in determining the icing state of the roadway.Attempts have been made to measure the coefficient of friction between atire and the roadway by placing strain gages in the tire tread.Naturally, such strain gages are ideal for the application of SAWtechnology especially since they can be interrogated wirelessly from adistance and they require no power for operation. As discussed above,SAW accelerometers can also perform this function. The measurement ofthe friction coefficient, however, is not predictive and the vehicleoperator is only able to ascertain the condition after the fact. SAWbased transducers have the capability of being interrogated as much as100 feet from the interrogator. Therefore, the judicious placement oflow-cost powerless SAW temperature and humidity sensors in or on theroadway at critical positions can provide an advance warning to vehicleoperators that road is slippery ahead. Such devices are very inexpensiveand therefore could be placed at frequent intervals along a highway.

[0457] An infrared sensor that looks down the highway in front of thevehicle can actually measure the road temperature prior to the vehicletraveling on that part of the roadway. This system also would not givesufficient warning if the operator waited for the occurrence of a frozenroadway. The probability of the roadway becoming frozen, on the otherhand, can be predicted long before it occurs, in most cases, by watchingthe trend in the temperature.

[0458] Some lateral control of the vehicle can also be obtained from SAWtransducers or electronic RFID tags placed down the center of the lane,either above the vehicles or in the roadway, for example. A vehiclehaving two receiving antennas approaching such devices, throughtriangulation, is able to determine the lateral location of the vehiclerelative to these SAW devices. If the vehicle also has an accurate mapof the roadway, the identification number associated with each suchdevice can be used to obtain highly accurate longitudinal positiondeterminations. Ultimately, the SAW devices can be placed on structuresbeside the road and perhaps on every mile or tenth of a mile marker. Ifthree antennas are used, as discussed herein, the distances to the SAWdevice can be determined.

[0459] Electronic RFID tags are also suitable for lateral andlongitudinal positioning purposes, however, the range available forelectronic RFID systems is considerably less than that of SAW basedsystems. On the other hand, as taught in U.S. provisional patentapplication Ser. No. 60/231,378, the time of flight of the RFID systemcan be used to determine the distance from the vehicle to the RFID tag.Because of the inherent delay in the SAW devices and its variation withtemperature, accurate distance measurement is probably not practicalbased on time of flight but somewhat less accurate distance measurementsbased on relative time of arrival can be made. Even if the exact delayimposed by the SAW device was accurately known at one temperature, suchdevices are usually reasonably sensitive to changes in temperature,hence they make good temperature sensors, and thus the accuracy of thedelay in the SAW device is more difficult to maintain. An interestingvariation of an electronic RFID that is particularly applicable to thisand other applications of this invention is disclosed in A. Pohl, L.Reindl, “New passive sensors”, Proc. 16th IEEE Instrumentation andMeasurement Technology Conf., IMTC/99, 1999, pp. 1251-1255. which isincorporated by reference herein in its entirety.

[0460] Many SAW devices are based on lithium niobate or similar strongpiezoelectric materials. Such materials have high thermal expansioncoefficients. An alternate material is quartz that has a very lowthermal expansion coefficient. However, its piezoelectric properties areinferior to lithium niobate. One solution to this problem is to uselithium niobate as the coupling system between the antenna and thematerial upon which the surface acoustic wave travels. In this matter,the advantages of a low thermal expansion coefficient material can beobtained while using the lithium niobate for its strong piezoelectricproperties. Other useful materials such as Langasite have propertiesthat are intermediate between lithium niobate and quartz. Note that itis also possible to use combinations of materials to achieve particularobjectives with property measurement since different materials responddifferently to different sensed properties or environments.

[0461] The use of SAW tags as an accurate precise positioning system asdescribed above would be applicable for accurate vehicle location, asdiscussed in U.S. patent application Ser. No. 09/177,041, for lanes intunnels, for example, or other cases where loss of satellite lock iscommon.

[0462] The various technologies discussed above can be used incombination. The electronic RFID tag can be incorporated into a SAW tagproviding a single device that provides both an instant reflection ofthe radio frequency waves as well as a re-transmission at a later time.This marriage of the two technologies permits the strengths of eachtechnology to be exploited in the same device. For most of theapplications described herein, the cost of mounting such a tag in avehicle or on the roadway far exceeds the cost of the tag itself.Therefore, combining the two technologies does not significantly affectthe cost of implementing tags onto vehicles or roadways or sidestructures.

[0463] An alternate method to the electronic RFID tag is to simply use aradar reflector and measure the time of flight to the reflector andback. The radar reflector can even be made of a series of reflectingsurfaces displaced from each other to achieve some simple coding.

[0464] Another field in which SAW technology can be applied is for“ultrasound-on-a-surface” type of devices.

[0465] U.S. Pat. No. 5,629,681, assigned to the same assignee herein andincorporated by reference herein, describes many uses of ultrasound in atube. Many of the applications are also candidates forultrasound-on-a-surface devices. In this case, a micromachined SAWdevice will in general be replaced by a much larger structure.

[0466] Touch screens based on surface acoustic waves are well known inthe art. The use of this technology for a touch pad for use with aheads-up display is disclosed in the current assignee's U.S. patentapplication Ser. No. 09/645,709. The use of surface acoustic waves ineither one or two dimensional applications has many other possible usessuch as for pinch protection on window and door closing systems, crushsensing crash sensors, occupant presence detector and butt printmeasurement systems, generalized switches such as on the circumferenceor center of the steering wheel, etc. Since these devices typicallyrequire significantly more power than the micromachined SAW devicesdiscussed above, most of these applications will require a powerconnection. On the other hand, the output of these devices can gothrough a SAW micromachined device or, in some other manner, be attachedto an antenna and interrogated using a remote interrogator thuseliminating the need for a direct wire communication link.

[0467] One example would be to place a surface acoustic wave device onthe circumference of the steering wheel. Upon depressing a section ofthis device, the SAW wave would be attenuated. The interrogator wouldnotify the acoustic wave device at one end of the device to launch anacoustic wave and then monitor output from the antenna. Depending on thephase, time delay, and/or amplitude of the output wave, the interrogatorwould know where the operator had depressed the steering wheel SAWswitch and therefore know the function desired by the operator.

[0468] Piezoelectric generators are another field in which SAWtechnology can be applied and the invention encompasses severalembodiments of SAW piezoelectric generators.

[0469] An alternate approach for some applications, such as tiremonitoring, where it is difficult to interrogate the SAW device as thewheel, and thus the antenna, is rotating, the transmitting power can besignificantly increased if there is a source of energy inside the tire.Many systems now use a battery but this leads to problems related tohaving to periodically replace the battery and temperature effects. Insome cases, the manufacturers recommend that the battery be replaced asoften as every 6 to 12 months. Batteries also sometimes fail to functionproperly at cold temperatures and have their life reduced when operatedat high temperatures. For these reasons, there is a strong belief that atire monitoring system should obtain its power from some source externalof the tire. Similar problems can be expected for other applications.

[0470] One novel solution to this problem is to use the flexing of thetire itself to generate electricity. If a thin film of PVDF is attachedto the tire inside and adjacent to the tread, then as the tire rotatesthe film will flex and generate electricity. This energy can then bestored on one or more capacitors and used to power the tire monitoringcircuitry. Also, since the amount of energy that is generated depends ofthe flexure of the tire, this generator can also be used to monitor thehealth of the tire in a similar manner as the generation 3 accelerometersystem described above.

[0471] As mentioned above, the transmissions from different SAW devicescan be time multiplexed by varying the delay time from device to device,frequency multiplexed by varying the natural frequencies of the SAWdevices, code multiplexed by varying the identification code of the SAWdevices or space multiplexed by using multiple antennas. Considering thetime multiplexing case, varying the length of the SAW device and thusthe delay before retransmission can separate different classes ofdevices. All seat sensors can have one delay which would be differentfrom tire monitors or light switches etc.

[0472] Referring now to FIGS. 13A-36B, a first embodiment of a valve cap10 including a tire pressure monitoring system in accordance with theinvention is shown generally at 10 in FIG. 13A. A tire 1 has aprotruding, substantially cylindrical valve stem 2 which is shown in apartial cutaway view in FIG. 13A. The valve stem 2 comprises a sleeve 3and a tire valve assembly 5. The sleeve 3 of the valve stem 2 isthreaded on both its inner surface and its outer surface. The tire valveassembly 5 is arranged in the sleeve 3 and includes threads on an outersurface which are mated with the threads on the inner surface of thesleeve 3. The valve assembly 5 comprises a valve seat 4 and a valve pin6 arranged in an aperture in the valve seat 4. The valve assembly 5 isshown in the open condition in FIG. 13A whereby air flows through apassage between the valve seat 4 and the valve pin 6.

[0473] The valve cap 10 includes a substantially cylindrical body 9 andis attached to the valve stem 2 by means of threads 8 arranged on aninner cylindrical surface of body 9 which are mated with the threads onthe outer surface of the sleeve 3. The valve cap 10 comprises a valvepin depressor 14 arranged in connection with the body 9 and a SAWpressure sensor 11. The valve pin depressor 14 engages the valve pin 6upon attachment of the valve cap 10 to the valve stem 2 and depresses itagainst its biasing spring, not shown, thereby opening the passagebetween the valve seat 4 and the valve pin 6 allowing air to pass fromthe interior of tire 1 into a reservoir or chamber 12 in the body 9.Chamber 12 contains the SAW pressure sensor 11 as described in moredetail below.

[0474] Pressure sensor 11 is an absolute pressure-measuring device. Itfunctions based on the principle that the increase in air pressure andthus air density in the chamber 12 increases the mass loading on a SAWdevice changing the velocity of surface acoustic wave on thepiezoelectric material. The pressure sensor 11 is therefore positionedin an exposed position in the chamber 12.

[0475] A second embodiment of a valve cap 10′ in accordance with theinvention is shown in FIG. 13B and comprises a SAW strain sensing device15 that is mounted onto a flexible membrane 13 attached to the body 9′of the valve cap 10′ and in a position in which it is exposed to the airin the chamber 12′. When the pressure changes in chamber 12′, thedeflection of the membrane 13 changes thereby changing the stress in theSAW device 15.

[0476] Strain sensor 15 is thus a differential pressure-measuringdevice. It functions based on the principle that changes in the flexureof the membrane 13 can be correlated to changes in pressure in thechamber 12′ and thus, if an initial pressure and flexure are known, thechange in pressure can be determined from the change in flexure.

[0477]FIGS. 13A and 13B therefore illustrate two different methods ofusing a SAW sensor in a valve cap for monitoring the pressure inside atire. The precise manner in which the SAW sensors 11,15 operate isdiscussed fully below but briefly, each sensor 11,15 includes an antennaand an interdigital transducer which receives a wave via the antennafrom an interrogator which proceeds to travel along a substrate. Thetime in which the waves travel across the substrate and return to theinterdigital transducer is dependent on the temperature, the massloading on the substrate (in the embodiment of FIG. 13A) or the flexureof membrane 13 (in the embodiment of FIG. 13B). The antenna transmits areturn wave which is receives and the time delay between the transmittedand returned wave is calculated and correlated to the pressure in thechamber 12 or 12′.

[0478] Sensors 11 and 15 are electrically connected to the metal valvecap 10 that is electrically connected to the valve stem 2. The valvestem 2 is electrically isolated from the tire rim and serves as anantenna for transmitting radio frequency electromagnetic signals fromthe sensors 11 and 15 to a vehicle mounted interrogator, not shown, tobe described in detail below. As shown in FIG. 13A., a pressure seal 16is arranged between an upper rim of the sleeve 3 and an inner shoulderof the body 9 of the valve cap 10 and serves to prevent air from flowingout of the tire 1 to the atmosphere.

[0479] The speed of the surface acoustic wave on the piezoelectricsubstrate changes with temperature in a predictable manner as well aswith pressure. For the valve cap implementations, a separate SAW devicecan be attached to the outside of the valve cap and protected with acover where it is subjected to the same temperature as the SAW sensors11 or 15 but is not subject to pressure or strain. This requires thateach valve cap comprise two SAW devices, one for pressure sensing andanother for temperature sensing. Since the valve cap is exposed toambient temperature, a preferred approach is to have a single device onthe vehicle which measures ambient temperature outside of the vehiclepassenger compartment. Many vehicles already have such a temperaturesensor. For those installations where access to this temperature data isnot convenient, a separate SAW temperature sensor can be mountedassociated with the interrogator antenna, as illustrated below, or someother convenient place.

[0480] Although the valve cap 10 is provided with the pressure seal 16,there is a danger that the valve cap 10 will not be properly assembledonto the valve stem 2 and a small quantity of the air will leak overtime. FIG. 14 provides an alternate design where the SAW temperature andpressure measuring devices are incorporated into the valve stem. Thisembodiment is thus particularly useful in the initial manufacture of atire.

[0481] The valve stem assembly is shown generally at 20 and comprises abrass valve stem 7 which contains a tire valve assembly 5. The valvestem 7 is covered with a coating 21 of a resilient material such asrubber, which has been partially removed in the drawing. A metalconductive ring 22 is electrically attached to the valve stem 7. Arubber extension 23 is also attached to the lower end of the valve stem7 and contains a SAW pressure and temperature sensor 24. The SAWpressure and temperature sensor 24 can be of at least two designswherein the SAW sensor is used as an absolute pressure sensor as shownin FIG. 14A or an as a differential sensor based on membrane strain asshown in FIG. 14B.

[0482] In FIG. 14A, the SAW sensor 24 comprises a capsule 32 having aninterior chamber in communication with the interior of the tire via apassageway 30. A SAW absolute pressure sensor 27 is mounted onto oneside of a rigid membrane or separator 31 in the chamber in the capsule32. Separator 31 divides the interior chamber of the capsule 32 into twocompartments 25 and 26, with only compartment 25 being in flowcommunication with the interior of the tire. The SAW absolute pressuresensor 27 is mounted in compartment 25 which is exposed to the pressurein the tire through passageway 30. A SAW temperature sensor 28 isattached to the other side of the separator 31 and is exposed to thepressure in compartment 26. The pressure in compartment 26 is unaffectedby the tire pressure and is determined by the atmospheric pressure whenthe device was manufactured and the effect of temperature on thispressure. The speed of sound on the SAW temperature sensor 28 is thusaffected by temperature but not by pressure in the tire.

[0483] The operation of SAW sensors 27 and 28 is discussed elsewheremore fully but briefly, since SAW sensor 27 is affected by the pressurein the tire, the wave which travels along the substrate is affected bythis pressure and the time delay between the transmission and receptionof a wave can be correlated to the pressure. Similarly, since SAW sensor28 is affected by the temperature in the tire, the wave which travelsalong the substrate is affected by this temperature and the time delaybetween the transmission and reception of a wave can be correlated tothe temperature.

[0484]FIG. 14B illustrates an alternate configuration of sensor 24 wherea flexible membrane 33 is used instead of the rigid separator 31 shownin the embodiment of FIG. 14A, and a SAW device is mounted on flexiblemember 33. In this embodiment, the SAW temperature sensor 28 is mountedto a different wall of the capsule 32. A SAW device 29 is thus affectedboth by the strain in membrane 33 and the absolute pressure in the tire.Normally, the strain effect will be much larger with a properly designedmembrane 33.

[0485] The operation of SAW sensors 28 and 29 is discussed elsewheremore fully but briefly, since SAW sensor 28 is affected by thetemperature in the tire, the wave which travels along the substrate isaffected by this temperature and the time delay between the transmissionand reception of a wave can be correlated to the temperature. Similarly,since SAW sensor 29 is affected by the pressure in the tire, the wavewhich travels along the substrate is affected by this pressure and thetime delay between the transmission and reception of a wave can becorrelated to the pressure.

[0486] In both of the embodiments shown in FIG. 14A and FIG. 14B, aseparate temperature sensor is illustrated. This has two advantages.First, it permits the separation of the temperature effect from thepressure effect on the SAW device. Second, it permits a measurement oftire temperature to be recorded. Since a normally inflated tire canexperience excessive temperature caused, for example, by an overloadcondition, it is desirable to have both temperature and pressuremeasurements of each vehicle tire

[0487] The SAW devices 27, 28 and 29 are electrically attached to thevalve stem 7 which again serves as an antenna to transmit radiofrequency information to an interrogator. This electrical connection canbe made by a wired connection; however, the impedance between the SAWdevices and the antenna may not be properly matched. An alternateapproach as described in Varadan, V. K. et al., “Fabrication,characterization and testing of wireless MEMS-IDT basedmicroaccelerometers” Sensors and Actuators A 90 (2001) p. 7-19, 2001Elsevier Netherlands, incorporated herein by reference, is toinductively couple the SAW devices to the brass tube.

[0488] Although an implementation into the valve stem and valve capexamples have been illustrated above, an alternate approach is to mountthe SAW temperature and pressure monitoring devices elsewhere within thetire. Similarly, although the tire stem in both cases above serves theantenna, in many implementations, it is preferable to have a separatelydesigned antenna mounted within or outside of the vehicle tire. Forexample, such an antenna can project into the tire from the valve stemor can be separately attached to the tire or tire rim either inside oroutside of the tire. In some cases, it can be mounted on the interior ofthe tire on the sidewall.

[0489] A more advanced embodiment of a tire monitor in accordance withthe invention is illustrated generally at 40 in FIGS. 15 and 15A. Inaddition to temperature and pressure monitoring devices as described inthe previous applications, the tire monitor assembly 40 comprises anaccelerometer of any of the types to be described below which isconfigured to measure either or both of the tangential and radialaccelerations. Tangential accelerations as used herein meanaccelerations tangent to the direction of rotation of the tire andradial accelerations as used herein mean accelerations toward or awayfrom the wheel axis. For either accelerometer case, the accelerationwill be zero when the monitor assembly 40 is closest to the road andwill be at a maximum when the monitor assembly 40 is at its maximumdistance from the road. Both accelerations will increase and decrease atall positions in between.

[0490] In FIG. 15, the tire monitor assembly 40 is cemented to theinterior of the tire opposite the tread. In FIG. 15A, the tire monitorassembly 40 is inserted into the tire opposite the tread duringmanufacture.

[0491] Superimposed on the acceleration signals will be vibrationsintroduced into tire from road interactions and due to tread separationand other defects. Additionally, the presence of the nail or otherobject attached to the tire will, in general, excite vibrations that canbe sensed by the accelerometers. When the tread is worn to the extentthat the wire belts 41 begin impacting the road, additional vibrationswill be induced.

[0492] Through monitoring the acceleration signals from the tangentialor radial accelerometers within the tire monitor assembly 40,delamination, a worn tire condition, imbedded nails, other debrisattached to the tire tread, hernias, can all be sensed. Additionally, aspreviously discussed, the length of time that the tire tread is incontact with the road opposite tire monitor 40 can be measured and,through a comparison with the total revolution time, the length of thetire footprint on the road can be determined. This permits the load onthe tire to be measured, thus providing an indication of excessive tireloading. As discussed above, a tire can fail due to over loading evenwhen the tire interior temperature and pressure are within acceptablelimits. Other tire monitors cannot sense such conditions.

[0493] Since the acceleration changes during the rotation of the tire, asimple switch containing an acceleration sensing mass can now bedesigned that would permit data transmission only during one part of thetire rotation. Such a switch can be designed, for example, such that itshorts out the antenna except when the tire is experiencing zeroacceleration at which time it permits the device to transmit data to theinterrogator. Such a system would save on battery power, for example,for powered systems and minimize bandwidth use for passive systems.

[0494] In the discussion above, the use of the tire valve stem as anantenna has been discussed. An antenna can also be placed within thetire when the tire sidewalls are not reinforced with steel. In somecases and for some frequencies, it is sometimes possible to use the tiresteel bead or steel belts as an antenna, which in some cases can becoupled to inductively. Alternately, the antenna can be designedintegral with the tire beads or belts and optimized and made part of thetire during manufacture.

[0495] Although the discussion above has centered on the use of SAWdevices, the configuration of FIG. 15 can also be effectivelyaccomplished with other pressure, temperature and accelerometer sensors.One of the advantages of using SAW devices is that they are totallypassive thereby eliminating the requirement of a battery. For theimplementation of tire monitor assembly 40, the changes in accelerationcan also be used to generate sufficient electrical energy to power asilicon microcircuit. In this configuration, additional devices,typically piezoelectric devices, are used as a generator of electricitythat can be stored in one or more conventional capacitors orultra-capacitors. Naturally, other types of electrical generators can beused such as those based on a moving coil and a magnetic field etc. APVDF piezoelectric polymer can also be used to generate electricalenergy based on the flexure of the tire as described below.

[0496]FIG. 16 illustrates an absolute pressure sensor based on surfaceacoustic wave (SAW) technology. A SAW absolute pressure sensor 50 has aninterdigital transducer (IDT) 51 which is connected to antenna 52. Uponreceiving an RF signal of the proper frequency, the antenna induces asurface acoustic wave in the material 53 which can be lithium niobate,quartz, zinc oxide, or other appropriate piezoelectric material. As thewave passes through a pressure sensing area 54 formed on the material53, its velocity is changed depending on the air pressure exerted on thesensing area 54. The wave is then reflected by reflectors 55 where itreturns to the IDT 51 and to the antenna 52 for retransmission back tothe interrogator. The material in the pressure sensing area 54 can be athin (such as one micron) coating of a polymer that absorbs orreversibly reacts with oxygen or nitrogen where the amount absorbeddepends on the air density.

[0497] In FIG. 16A, two additional sections of the SAW device,designated 56 and 57, are provided such that the air pressure affectssections 56 and 57 differently than pressure sensing area 54. This isachieved by providing three reflectors. The three reflecting areas causethree reflected waves to appear, 59, 60 and 61 when input wave 62 isprovided. The spacing between waves 59 and 60, and between waves 60 and61 provides a measure of the pressure. This construction of a pressuresensor may be utilized in the embodiments of FIGS. 13A-15 or in anyembodiment wherein a pressure measurement by a SAW device is obtained.

[0498] There are many other ways in which the pressure can be measuredbased on either the time between reflections or on the frequency orphase change of the SAW device as is well known to those skilled in theart. FIG. 16B, for example, illustrates an alternate SAW geometry whereonly two sections are required to measure both temperature and pressure.This construction of a temperature and pressure sensor may be utilizedin the embodiments of FIGS. 13A-15 or in any embodiment wherein both apressure measurement and a temperature measurement by a single SAWdevice is obtained.

[0499] Another method where the speed of sound on a piezoelectricmaterial can be changed by pressure was first reported in Varadan etal., “Local/Global SAW Sensors for Turbulence” referenced above. This,phenomenon has not been applied to solving pressure sensing problemswithin an automobile until now. The instant invention is believed to bethe first application of this principle to measuring tire pressure, oilpressure, coolant pressure, pressure in a gas tank, etc. Experiments todate, however, have been unsuccessful.

[0500] In some cases, a flexible membrane is placed loosely over the SAWdevice to prevent contaminants from affecting the SAW surface. Theflexible membrane permits the pressure to be transferred to the SAWdevice without subjecting the surface to contaminants. Such a flexiblemembrane can be used in most if not all of the embodiments describedherein.

[0501] A SAW temperature sensor 60 is illustrated in FIG. 17. Since theSAW material, such as lithium niobate, expands significantly withtemperature, the natural frequency of the device also changes. Thus, fora SAW temperature sensor to operate, a material for the substrate isselected which changes its properties as a function of temperature,i.e., expands. Similarly, the time delay between the insertion andretransmission of the signal also varies measurably. Since speed of asurface wave is typically 100,000 times slower then the speed of light,usually the time for the electromagnetic wave to travel to the SAWdevice and back is small in comparison to the time delay of the SAW waveand therefore the temperature is approximately the time delay betweentransmitting electromagnetic wave and its reception.

[0502] An alternate approach as illustrated in FIG. 17A is to place athermistor 62 across an interdigital transducer (IDT) 61, which is nownot shorted as it was in FIG. 17. In this case, the magnitude of thereturned pulse varies with the temperature. Thus, this device can beused to obtain two independent temperature measurements, one based ontime delay or natural frequency of the device 60 and the other based onthe resistance of the thermistor 62.

[0503] When some other property such as pressure is being measured bythe device 65 as shown in FIG. 17B, two parallel SAW devices arecommonly used. These devices are designed so that they responddifferently to one of the parameters to be measured. Thus, SAW device 66and SAW device 67 can be designed to both respond to temperature andrespond to pressure. However, SAW device 67, which contains a surfacecoating, will respond differently to pressure than SAW device 66. Thus,by measuring natural frequency or the time delay of pulses inserted intoboth SAW devices 66 and 67, a determination can be made of both thepressure and temperature, for example. Naturally, the device which isrendered sensitive to pressure in the above discussion could alternatelybe rendered sensitive to some other property such as the presence orconcentration of a gas, vapor, or liquid chemical as described in moredetail below.

[0504] An accelerometer that can be used for either radial or tangentialacceleration in the tire monitor assembly of FIG. 15 is illustrated inFIGS. 18 and 18A. The design of this accelerometer is explained indetail in Varadan, V. K. et al., “Fabrication, characterization andtesting of wireless MEMS-IDT based microaccelerometers” referencedabove, which is incorporated in its entirety herein by reference, andwill not be repeated herein.

[0505] A stud which is threaded on both ends and which can be used tomeasure the weight of an occupant seat is illustrated in FIGS. 19A-19D.The operation of this device is disclosed in U.S. patent applicationSer. No. 09/849,558 wherein the center section of stud 101 is solid. Ithas been discovered that sensitivity of the device can be significantlyimproved if a slotted member is used as described in U.S. Pat. No.5,539,236, which is incorporated herein by reference. FIG. 19Aillustrates a SAW strain gage 102 mounted on a substrate and attached tospan a slot 104 in a center section 105 of the stud 101. This techniquecan be used with any other strain-measuring device.

[0506]FIG. 19B is a side view of the device of FIG. 19A.

[0507]FIG. 19C illustrates use of a single hole 106 drilled off-centerin the center section 105 of the stud 101. A single hole 106 also servesto magnify the strain as sensed by the strain gage 102. It has theadvantage in that strain gage 102 does not need to span an open space.The amount of magnification obtained from this design, however, issignificantly less than obtained with the design of FIG. 19A.

[0508] To improve the sensitivity of the device shown in FIG. 19C,multiple smaller holes 107 can be used as illustrated in FIG. 19D. FIG.19E in an alternate configuration showing four gages for determining thebending moments as well as the axial stress in the support member.

[0509] In operation, the SAW strain gage 102 receives radio frequencywaves from an interrogator 110 and returns electromagnetic waves via arespective antenna 103 which are delayed based on the strain sensed bystrain gage 102.

[0510] A SAW device can also be used as a wireless switch as shown inFIGS. 20A and 20B. FIG. 20A shows a surface 120 containing a projection122 on top of a SAW device 121. Surface material 120 could be, forexample, the armrest of an automobile, the steering wheel airbag cover,or any other surface within the passenger compartment of an automobileor elsewhere. Projection 122 will typically be a material capable oftransmitting force to the surface of SAW device 121. As shown in FIG.20B, a projection 123 may be placed on top of the SAW device 124. Thisprojection 123 permits force exerted on the projection 122 to create apressure on the SAW device 124. This increased pressure changes the timedelay or natural frequency of the SAW wave traveling on the surface ofmaterial. Alternately, it can affect the magnitude of the returnedsignal. The projection 123 is typically held slightly out of contactwith the surface until forced into contact with it.

[0511] An alternate approach is to place a switch across the IDT 127 asshown in FIG. 20C. If switch 125 is open, then the device will notreturn a signal to the interrogator. If it is closed, than the IDT 127will act as a reflector sending a single back to IDT 128 and thus to theinterrogator. Alternately, a switch 126 can be placed across the SAWdevice. In this case, a switch closure shorts the SAW device and nosignal is returned to the interrogator. For the embodiment of FIG. 20C,using switch 126 instead of switch 125, a standard reflector IDT wouldbe used in place of the IDT 127.

[0512] Most SAW-based accelerometers work on the principle of strainingthe SAW surface and thereby changing either the time delay or naturalfrequency of the system. An alternate novel accelerometer is illustratedFIG. 21A wherein a mass 130 is attached to a silicone rubber coating 131which has been applied the SAW device. Acceleration of the mass in FIG.21 in the direction of arrow X changes the amount of rubber in contactwith the surface of the SAW device and thereby changes the damping,natural frequency or the time delay of the device. By this method,accurate measurements of acceleration below 1 G are readily obtained.Furthermore, this device can withstand high deceleration shocks withoutdamage. FIG. 21B illustrates a more conventional approach where thestrain in a beam 137 caused by the acceleration acting on a mass 136 ismeasured with a SAW strain sensor 135.

[0513] It is important to note that all of these devices have a highdynamic range compared with most competitive technologies. In somecases, this dynamic range can exceed 100,000. This is the direct resultof the ease with which frequency and phase can be accurately measured.

[0514] A gyroscope, which is suitable for automotive applications, isillustrated in FIG. 22 and described in detail in V. K. Varadan'sInternational Application No. WO 00/79217, which is incorporated byreference herein in its entirety. This SAW-based gyroscope hasapplicability for the vehicle navigation, dynamic control, and rolloversensing among others.

[0515] Note that any of the disclosed applications can be interrogatedby the central interrogator of this invention and can either be poweredor operated powerlessly as described in general above. Block diagrams ofthree interrogators suitable for use in this invention are illustratedin FIGS. 23A-23C. FIG. 23A illustrates a superheterodyne circuit andFIG. 23B illustrates a dual superheterodyne circuit. FIG. 23C operatesas follows. During the burst time two frequencies, F1 and F1+F2, aresent by the transmitter after being generated by mixing using oscillatorOsc. The two frequencies are needed by the SAW transducer where they aremixed yielding F2 which is modulated by the SAW and contains theinformation. Frequency (F1+F2) is sent only during the burst time whilefrequency F1 remains on until the signal F2 returns from the SAW. Thissignal is used for mixing. The signal returned from the SAW transducerto the interrogator is F1+F2 where F2 has been modulated by the SAWtransducer. It is expected that the mixing operations will result inabout 12 db loss in signal strength.

[0516]FIG. 24 illustrates a central antenna mounting arrangement forpermitting interrogation of the tire monitors for four tires and issimilar to that described in U.S. Pat. No. 4,237,728, which isincorporated by reference herein. An antenna package 200 is mounted onthe underside of the vehicle and communicates with devices 201 throughtheir antennas as described above. In order to provide for antennas bothinside (for example for weight sensor interrogation) and outside of thevehicle, another antenna assembly (not shown) can be mounted on theopposite side of the vehicle floor from the antenna assembly 200.

[0517]FIG. 24A is a schematic of the vehicle shown in FIG. 24. Theantenna package 200, which can be considered as an electronics module,contains a time domain multiplexed antenna array that sends and receivesdata from each of the five tires (including the spare tire), one at atime. It comprises a microstrip or stripline antenna array and amicroprocessor on the circuit board The antennas that face each tire arein an X configuration so that the transmissions to and from the tire canbe accomplished regardless of the tire rotation angle.

[0518] Based on the frequency and power available, and on FCClimitations, SAW devices can be designed to permit transmissiondistances of up to 100 feet or more. Since SAW devices can measure bothtemperature and humidity, they are also capable of monitoring roadconditions in front of and around a vehicle. Thus, a properly equippedvehicle can determine the road conditions prior to entering a particularroad section if such SAW devices are embedded in the road surface or onmounting structures close to the road surface as shown at 279 in FIG.25. Such devices could provide advance warning of freezing conditions,for example. Although at 60 miles per hour, such devices may onlyprovide a one second warning, this can be sufficient to provideinformation to a driver to prevent dangerous skidding. Additionally,since the actual temperature and humidity can be reported, the driverwill be warned prior to freezing of the road surface. SAW device 279 isshown in detail in FIG. 25A.

[0519] If a SAW device 283 is placed in a roadway, as illustrated inFIG. 26, and if a vehicle 290 has two receiving antennas 280 and 281, aninterrogator can transmit a signal from either of the two antennas andat a later time, the two antennas will receive the transmitted signalfrom the SAW device. By comparing the arrival time of the two receivedpulses, the position of vehicle on a lane can precisely determined(since the direction from each antenna 280,281 to the SAW device 283 canbe calculated). If the SAW device 283 has an identification code encodedinto the returned signal generated thereby, then the vehicle 290 candetermine, providing a precise map is available, its position on thesurface of the earth. If another antenna 286 is provided, for example,at the rear of the vehicle 290 then the longitudinal position of thevehicle can also be accurately determined as the vehicle passes the SAWdevice 283. Of course the SAW device 283 need not be in the center ofthe road. Alternate locations for positioning of the SAW device 283 areon overpasses above the road and on poles such as 284 and 285 on theroadside. Such a system has an advantage over a competing system usingradar and reflectors in that it is easier to measure the relative timebetween the two received pulses than it is to measure time of flight ofa radar signal to a reflector and back. Such a system operates in allweather conditions and is known as a precise location system. Eventuallysuch a SAW device 283 can be placed every tenth of a mile along theroadway or at some other appropriate spacing.

[0520] If a vehicle is being guided by a DGPS and accurate map systemsuch as disclosed in U.S. Pat. application Ser. No. 09/679,317 filedOct. 4, 2000, which is incorporated by reference herein, a problemarises when the GPS receiver system looses satellite lock as wouldhappen when the vehicle enters a tunnel, for example. If a preciselocation system as described above is placed at the exit of the tunnelthen the vehicle will know exactly where it is and can re-establishsatellite lock in as little as one second rather than typically 15seconds as might otherwise be required. Other methods making use of thecell phone system can be used to establish an approximate location ofthe vehicle suitable for rapid acquisition of satellite lock asdescribed in G. M. Djuknic, R. E. Richton “Geolocation and AssistedGPS”, Computer Magazine, February 2001, IEEE Computer Society, which isincorporated by reference herein in its entirety.

[0521] More particularly, geolocation technologies that rely exclusivelyon wireless networks such as time of arrival, time difference ofarrival, angle of arrival, timing advance, and multipath fingerprintingoffer a shorter time-to-first-fix (TTFF) than GPS. They also offer quickdeployment and continuous tracking capability for navigationapplications, without the added complexity and cost of upgrading orreplacing any existing GPS receiver in vehicles. Compared to eithermobile-station-based, stand-alone GPS or network-based geolocation,assisted-GPS (AGPS) technology offers superior accuracy, availability,and coverage at a reasonable cost. AGPS for use with vehicles wouldcomprise a communications unit with a partial GPS receiver arranged inthe vehicle, an AGPS server with a reference GPS receiver that cansimultaneously “see” the same satellites as the communications unit, anda wireless network infrastructure consisting of base stations and amobile switching center. The network can accurately predict the GPSsignal the communication unit will receive and convey that informationto the mobile, greatly reducing search space size and shortening theTTFF from minutes to a second or less. In addition, an AGPS receiver inthe communication unit can detect and demodulate weaker signals thanthose that conventional GPS receivers require. Because the networkperforms the location calculations, the communication unit only needs tocontain a scaled-down GPS receiver. It is accurate within about 15meters when they are outdoors, an order of magnitude more sensitive thanconventional GPS.

[0522] Since an AGPS server can obtain the vehicle's position from themobile switching center, at least to the level of cell and sector, andat the same time monitor signals from GPS satellites seen by mobilestations, it can predict the signals received by the vehicle for anygiven time. Specifically, the server can predict the Doppler shift dueto satellite motion of GPS signals received by the vehicle, as well asother signal parameters that are a function of the vehicle's location.In a typical sector, uncertainty in a satellite signal's predicted timeof arrival at the vehicle is about ±5 ps, which corresponds to ±5 chipsof the GPS coarse acquisition (C/A) code. Therefore, an AGPS server canpredict the phase of the pseudorandom noise (PRN) sequence that thereceiver should use to despread the C/A signal from a particularsatellite—each GPS satellite transmits a unique PRN sequence used forrange measurements—and communicate that prediction to the vehicle. Thesearch space for the actual Doppler shift and PRN phase is thus greatlyreduced, and the AGPS receiver can accomplish the task in a fraction ofthe time required by conventional GPS receivers. Further, the AGPSserver maintains a connection with the vehicle receiver over thewireless link, so the requirement of asking the communication unit tomake specific measurements, collect the results, and communicate themback is easily met. After despreading and some additional signalprocessing, an AGPS receiver returns back “pseudoranges” —that is,ranges measured without taking into account the discrepancy betweensatellite and receiver clocks—to the AGPS server, which then calculatesthe vehicle's location. The vehicle can even complete the location fixitself without returning any data to the server.

[0523] Sensitivity assistance, also known as modulation wipe-off,provides another enhancement to detection of GPS signals in thevehicle's receiver. The sensitivity-assistance message containspredicted data bits of the GPS navigation message, which are expected tomodulate the GPS signal of specific satellites at specified times. Themobile station receiver can therefore remove bit modulation in thereceived GPS signal prior to coherent integration. By extending coherentintegration beyond the 20-ms GPS data-bit period—to a second or morewhen the receiver is stationary and to 400 ms when it isfast-moving-this approach improves receiver sensitivity. Sensitivityassistance provides an additional 3-to-4-dB improvement in receiversensitivity. Because some of the gain provided by the basicassistance—code phases and Doppler shift values—is lost when integratingthe GPS receiver chain into a mobile system, this can prove crucial tomaking a practical receiver.

[0524] Achieving optimal performance of sensitivity assistance inTIA/EIA-95 CDMA systems is relatively straightforward because basestations and mobiles synchronize with GPS time. Given that global systemfor mobile communication (GSM), time division multiple access (TDMA), oradvanced mobile phone service (AMPS) systems do not maintain suchstringent synchronization, implementation of sensitivity assistance andAGPS technology in general will require novel approaches to satisfy thetiming requirement. The standardized solution for GSM and TDMA adds timecalibration receivers in the field—location measurement units—that canmonitor both the wireless-system timing and GPS signals used as a timingreference.

[0525] Many factors affect the accuracy of geolocation technologies,especially terrain variations such as hilly versus flat andenvironmental differences such as urban versus suburban versus rural.Other factors, like cell size and interference, have smaller butnoticeable effects. Hybrid approaches that use multiple geolocationtechnologies appear to be the most robust solution to problems ofaccuracy and coverage.

[0526] AGPS provides a natural fit for hybrid solutions because it usesthe wireless network to supply assistance data to GPS receivers invehicles. This feature makes it easy to augment the assistance-datamessage with low-accuracy distances from receiver to base stationsmeasured by the network equipment. Such hybrid solutions benefit fromthe high density of base stations in dense urban environments, which arehostile to GPS signals. Conversely, rural environments—where basestations are too scarce for network-based solutions to achieve highaccuracy- provide ideal operating conditions for AGPS because GPS workswell there.

[0527] SAW transponders can also be placed in the license plates 287(FIG. 26) of all vehicles at nominal cost. An appropriately equippedautomobile can then determine the angular location of vehicles in itsvicinity. If a third antenna 286 is placed at the center of the vehiclefront, then an indication of the distance to a license plate of apreceding vehicle can also be obtained as described above. Thus, onceagain, a single interrogator coupled with multiple antenna systems canbe used for many functions. Alternately, if more than one SAWtransponders is placed spaced apart on a vehicle and if two antennas areon the other vehicle, then the direction and position of the SAW vehiclecan be determined by the receiving vehicle.

[0528] A general SAW temperature and pressure gage which can be wirelessand powerless is shown generally at 300 located in the sidewall 310 of afluid container 320 in FIG. 27. A pressure sensor 301 is located on theinside of the container 320, where it measures deflection of thecontainer wall, and the fluid temperature sensor 302 on the outside. Thetemperature measuring SAW 300 can be covered with an insulating materialto avoid influence from the ambient temperature outside of the container320.

[0529] A SAW load sensor can also be used to measure load in the vehiclesuspension system powerless and wirelessly as shown in FIG. 28. FIG. 28Aillustrates a strut 315 such as either of the rear struts of the vehicleof FIG. 28. A coil spring 320 stresses in torsion as the vehicleencounters disturbances from the road and this torsion can be measuredusing SAW strain gages as described in U.S. Pat. No. 5,585,571 formeasuring the torque in shafts. This concept is also disclosed in U.S.Pat. No. 5,714,695. The disclosures of both patents are incorporatedherein by reference. The use of SAW strain gages to measure thetorsional stresses in a spring, as shown in FIG. 28B, and in particularin an automobile suspension spring has, to the knowledge of theinventors, not been heretofore disclosed. In FIG. 28B, the strainmeasured by SAW strain gage 322 is subtracted from the strain measuredby SAW strain gage 321 to get the temperature compensated strain inspring 320.

[0530] Since a portion of the dynamic load is also carried by the shockabsorber, the SAW strain gages 321 and 322 will only measure the steadyor average load on the vehicle. However, additional SAW strain gages 325can be placed on a piston rod 326 of the shock absorber to obtain thedynamic load. These load measurements can then be used for active orpassive vehicle damping or other stability control purposes.

[0531]FIG. 29 illustrates a vehicle passenger compartment, and theengine compartment, with multiple SAW temperature sensors 330. SAWtemperature sensors are distributed throughout the passengercompartment, such as on the A-pillar, on the B-pillar, on the steeringwheel, on the seat, on the ceiling, on the headliner, and on the rearglass and generally in the engine compartment. These sensors, which canbe independently coded with different IDs and different delays, canprovide an accurate measurement of the temperature distribution withinthe vehicle interior. Such a system can be used to tailor the heatingand air conditioning system based on the temperature at a particularlocation in the passenger compartment. If this system is augmented withoccupant sensors, then the temperature can be controlled based on seatoccupancy and the temperature at that location. If the occupant sensorsystem is based on ultrasonics than the temperature measurement systemcan be used to correct the ultrasonic occupant sensor system for thespeed of sound within the passenger compartment. Without such acorrection, the error in the sensing system can be as large as about 20percent.

[0532] In one case, the SAW temperature sensor can be made from PVDFfilm and incorporated within the ultrasonic transducer assembly. For the40 kHz ultrasonic transducer case, for example, the SAW temperaturesensor would return the several pulses sent to drive the ultrasonictransducer to the control circuitry using the same wires used totransmit the pulses to the transducer after a delay that is proportionalto the temperature within the transducer housing. Thus a very economicaldevice can add this temperature sensing function using much of the samehardware that is already present for the occupant sensing system. Sincethe frequency is low, PVDF could be fabricated into a very low costtemperature sensor for this purpose. Other piezoelectric materials couldalso be used.

[0533] Other sensors can be combined with the temperature sensors 330,or used separately, to measure carbon dioxide, carbon monoxide, alcohol,humidity or other desired chemicals as discussed above.

[0534] The SAW temperature sensors 330 provide the temperature at theirmounting location to a processor unit 332 via an interrogator with theprocessor unit including appropriate control algorithms for controllingthe heating and air conditioning system based on the detectedtemperatures. The processor unit can control, e.g., which vents in thevehicle are open and closed, the flow rate through vents and thetemperature of air passing through the vents. In general, the processorunit can control whatever adjustable components are present or form partof the heating and air conditioning system.

[0535] As shown in FIG. 29, a child seat 334 is present on the rearvehicle seat. The child seat 334 can be fabricated with one or more RFIDtags or SAW tags 336. The RFID tag(s) and SAW tag(s) can be constructedto provide information on the occupancy of the child seat, i.e., whethera child is present, based on the weight. Also, the mere transmission ofwaves from the RFID tag(s) or SAW tag(s) on the child seat would beindicative of the presence of a child seat. The RFID tag(s) and SAWtag(s) can also be constructed to provide information about theorientation of the child seat, i.e., whether it is facing rearward orforward. Such information about the presence and occupancy of the childseat and its orientation can be used in the control of vehicularsystems, such as the vehicle airbag system. In this case, a processorwould control the airbag system and would receive information from theRFID tag(s) and SAW tag(s) via an interrogator.

[0536] There are many applications for which knowledge of the pitchand/or roll orientation of a vehicle or other object is desired. Anaccurate tilt sensor can be constructed using SAW devices. Such a sensoris illustrated in FIG. 30A and designated 350. This sensor 350 utilizesa substantially planar and rectangular mass 351 and four supporting SAWdevices 352 which are sensitive to gravity. For example, the mass act todeflect a membrane on which the SAW device resides thereby straining theSAW device. Other properties can also be used for a tilt sensor such asthe direction of the earth's magnetic field. SAW devices 352 are shownarranged at the corners of the planar mass 351, but it must beunderstood that this arrangement is a preferred embodiment only and notintended to limit the invention. A fifth SAW device 353 can be providedto measure temperature. By comparing the outputs of the four SAW devices352, the pitch and roll of the automobile can be measured. This sensor350 can be used to correct errors in the SAW rate gyros described above.If the vehicle has been stationary for a period of time, the yaw SAWrate gyro can initialized to 0 and the pitch and roll SAW gyrosinitialized to a value determined by the tilt sensor of FIG. 30A. Manyother geometries of tilt sensors utilizing one or more SAW devices cannow be envisioned for automotive and other applications. In particular,an alternate preferred configuration is illustrated in FIG. 30B where atriangular geometry is used. In this embodiment, the planar mass istriangular and the SAW devices 352 are arranged at the corners, althoughas with FIG. 30A, this is a non-limiting, preferred embodiment.

[0537] Either of the SAW accelerometers described above can be utilizedfor crash sensors as shown in FIG. 31. These accelerometers have asubstantially higher dynamic range than competing accelerometers nowused for crash sensors such as those based on MEMS silicon springs andmasses and others based on MEMS capacitive sensing. As discussed above,this is partially a result of the use of frequency or phase shifts whichcan be easily measured over a very wide range. Additionally, manyconventional accelerometers that are designed for low accelerationranges are unable to withstand high acceleration shocks withoutbreaking. This places practical limitations on many accelerometerdesigns so that the stresses in the silicon springs are not excessive.Also for capacitive accelerometers, there is a narrow limit over whichdistance, and thus acceleration, can be measured.

[0538] The SAW accelerometer for this particular crash sensor design ishoused in a container 361 which is assembled into a housing 362 andcovered with a cover 363. This particular implementation shows aconnector 364 indicating that this sensor would require power and theresponse would be provided through wires. Alternately, as discussed forother devices above, the connector 364 can be eliminated and theinformation and power to operate the device transmitted wirelessly. Suchsensors can be used as frontal, side or rear impact sensors. They can beused in the crush zone, in the passenger compartment or any otherappropriate vehicle location If two such sensors are separated and haveappropriate sensitive axes, then the angular acceleration of the vehiclecan be also be determined. Thus, for example, forward-facingaccelerometers mounted in the vehicle side doors can used to measure theyaw acceleration of the vehicle. Alternately two vertical sensitive axisaccelerometers in the side doors can be used to measure the rollacceleration of vehicle, which would be useful for rollover sensing.

[0539] Although piezoelectric SAW devices normally use rigid materialsuch as quartz or lithium niobate, it is also possible to utilizepolyvinylidene fluoride (PVDF) providing the frequency is low. A pieceof PVDF film can also be used as a sensor of tire flexure by itself.Such a sensor is illustrated in FIGS. 32 and 32A at 400. The output offlexure of the PVDF film can be used to supply power to a siliconmicrocircuit that contains pressure and temperature sensors. Thewaveform of the output from the PVDF film also provides information asto the flexure of an automobile tire and can be used to diagnoseproblems with the tire as well as the tire footprint in a manner similarto the device described in FIG. 15. In this case, however, the PVDF filmsupplies sufficient power to permit significantly more transmissionenergy to be provided. The frequency and informational content can bemade compatible with the SAW interrogator described above such that thesame interrogator can be used. The power available for the interrogator,however, can be significantly greater thus increasing the reliabilityand reading range of the system.

[0540] There is a general problem with tire pressure monitors as well assystems that attempt to interrogate passive SAW or electronic RFID typedevices in that the FCC severely limits the frequencies and radiatingpower that can be used. Once it becomes evident that these systems willeventually save many lives, the FCC can be expected to modify theirposition. In the meantime, various schemes can be used to help alleviatethis problem. The lower frequencies that have been opened for automotiveradar permit higher power to be used and they could be candidates forthe devices discussed above. It is also possible, in some cases, totransmit power on multiple frequencies and combine the received power toboost the available energy. Energy can of course be stored andperiodically used to drive circuits and work is ongoing to reduce thevoltage required to operate semiconductors. The devices of thisinvention will make use of some or all of these developments as theytake place.

[0541] If the vehicle has been at rest for a significant time period,power will leak from the storage capacitors and will not be availablefor transmission. However, a few tire rotations are sufficient toprovide the necessary energy.

[0542] U.S. patent application Ser. No. 08/819,609, assigned to thecurrent assignee of this invention, provides multiple means fordetermining the amount of gas in a gas tank. Using the SAW pressuredevices of this invention, multiple pressure sensors can be placed atappropriate locations within a fuel tank to measure the fluid pressureand thereby determine the quantity of fuel remaining in the tank. Thisis illustrated in FIG. 33. In this example, four SAW pressuretransducers 402 are placed on the bottom of the fuel tank and one SAWpressure transducer 403 is placed at the top of the fuel tank toeliminate the effects of vapor pressure within tank. Using neuralnetworks, or other pattern recognition techniques, the quantity of fuelin the tank can be accurately determined from these pressure readings ina manner similar that described the '609 patent application. The SAWmeasuring device illustrated in FIG. 33A combines temperature andpressure measurements in a single unit using parallel paths 405 and 406in the same manner as described above

[0543] Occupant weight sensors can give erroneous results if theseatbelt is pulled tight pushing the occupant into the seat. This isparticularly a problem when the seatbelt is not attached to the seat.For such cases, it has been proposed to measure the tension in variousparts of the seatbelt. Using conventional technology requires that suchdevices be hard-wired into the vehicle complicating the wire harness.

[0544] With reference to FIG. 34, using a SAW strain gage as describedabove, the tension in the seat belt 500 can be measured without therequirement of power or signal wires. FIG. 34 illustrates a powerlessand wireless passive SAW strain gage based device 502 for this purpose.There are many other places that such a device can be mounted to measurethe tension in the seatbelt at one or at multiple places.

[0545]FIG. 35 illustrates another version of a tire temperature and/orpressure monitor 510. Monitor 510 may include at an inward end, any oneof the temperature transducers or sensors described above and/or any oneof the pressure transducers or sensors described above, or any one ofthe combination temperature and pressure transducers or sensorsdescribed above.

[0546] The monitor 510 has an elongate body attached through the wheelrim 513 typically on the inside of the tire so that the under-vehiclemounted antenna(s) have a line of sight view of antenna 515. Monitor 510is connected to an inductive wire 512, which matches the output of thedevice with the antenna 515, which is part of the device assembly.Insulating material 511 surrounds the body which provides an air tightseal and prevents electrical contact with the wheel rim 513.

[0547]FIG. 36A shows a schematic of a prior art airbag module deploymentscheme in which sensors, which detect data for use in determiningwhether to deploy an airbag in the airbag module, are wired to anelectronic control unit (ECU) and a command to initiate deployment ofthe airbag in the airbag module is sent wirelessly.

[0548] By contrast, as shown in FIG. 36B, in accordance with theinvention, the sensors are wireless connected to the electronic controlunit and thus transmit data wirelessly. The ECU is however wired to theairbag module.

[0549] SAW sensors also have applicability to various other sectors ofthe vehicle, including the powertrain, chassis, and occupant comfort andconvenience. For example, SAW sensors have applicability to sensors forthe powertrain area including oxygen sensors, gear-tooth Hall effectsensors, variable reluctance sensors, digital speed and positionsensors, oil condition sensors, rotary position sensors, low pressuresensors, manifold absolute pressure/manifold air temperature (MAP/MAT)sensors, medium pressure sensors, turbo pressure sensors, knock sensors,coolant/fluid temperature sensors, and transmission temperature sensors.

[0550] SAW sensors for chassis applications include gear-tooth Halleffect sensors, variable reluctance sensors, digital speed and positionsensors, rotary position sensors, non-contact steering position sensors,and digital ABS (anti-lock braking system) sensors.

[0551] SAW sensors for the occupant comfort and convenience area includelow-pressure sensors, IVAC temperature and humidity sensors, airtemperature sensors, and oil condition sensors.

[0552] SAW sensors also have applicability such areas as controllingevaporative emissions, transmission shifting, mass air flow meters,oxygen, NOx and hydrocarbon sensors. SAW based sensors are particularlyuseful in high temperature environments where many other technologiesfail.

[0553] SAW sensors can facilitate compliance with U.S. regulationsconcerning evaporative system monitoring in vehicles, through a SAW fuelvapor pressure and temperature sensors that measure fuel vapor pressurewithin the fuel tank as well as temperature. If vapors leak into theatmosphere, the pressure within the tank drops. The sensor notifies thesystem of a fuel vapor leak, resulting in a warning signal to the driverand/or notification to a repair facility. This application isparticularly important since the condition within the furl tank can beascertained wirelessly reducing the chance of a fuel fire in anaccident. The same interrogator that monitors the tire pressure SAWsensors can also monitor the fuel vapor pressure and temperature sensorsresulting in significant economies.

[0554] A SAW humidity sensor can be used for measuring the relativehumidity and the resulting information can be input to the enginemanagement system or the heating, ventilation, and air conditioning(HVAC) system for more efficient operation. The relative humidity of theair entering an automotive engine impacts the engine's combustionefficiency; i.e., the ability of the spark plugs to ignite the fuel/airmixture in the combustion chamber at the proper time. A SAW humiditysensor in this case can measure the humidity level of the incomingengine air, helping to calculate a more precise fuel/air ratio forimproved fuel economy and reduced emissions.

[0555] Dew point conditions are reached when the air is fully saturatedwith water. When the cabin dew point temperature matches the windshieldglass temperature, water from the air condenses quickly, creating frostor fog. A SAW humidity sensor with a temperature-sensing element and awindow glass-temperature-sensing element can prevent the formation ofvisible fog formation by automatically controlling the HVAC system.

[0556] Among the inventions disclosed above is an arrangement forobtaining and conveying information about occupancy of a passengercompartment of a vehicle comprises at least one wave-receiving sensorfor receiving waves from the passenger compartment, generating meanscoupled to the wave-receiving sensor(s) for generating information aboutthe occupancy of the passenger compartment based on the waves receivedby the wave-receiving sensor(s) and communications means coupled to thegenerating means for transmitting the information about the occupancy ofthe passenger compartment. As such, response personnel can receive theinformation about the occupancy of the passenger compartment and respondappropriately, if necessary. There may be several wave-receiving sensorsand they may be, e.g., ultrasonic wave-receiving sensors,electromagnetic wave-receiving sensors, capacitance or electric fieldsensors, or combinations thereof. The information about the occupancy ofthe passenger compartment can include the number of occupants in thepassenger compartment, as well as whether each occupant is movingnon-reflexively and breathing. A transmitter may be provided fortransmitting waves into the passenger compartment such that eachwave-receiving sensor receives waves transmitted from the transmitterand modified by passing into and at least partially through thepassenger compartment. One or more memory units may be coupled to thegenerating means for storing the information about the occupancy of thepassenger compartment and to the communications means. Thecommunications means then can interrogate the memory unit(s) upon acrash of the vehicle to thereby obtain the information about theoccupancy of the passenger compartment. In one particularly usefulembodiment, means for determining the health state of at least oneoccupant are provided, e.g., a heartbeat sensor, a motion sensor such asa micropower impulse radar sensor for detecting motion of the at leastone occupant and motion sensor for determining whether the occupant(s)is/are breathing, and coupled to the communications means. Thecommunications means can interrogate the health state determining meansupon a crash of the vehicle to thereby obtain and transmit the healthstate of the occupant(s). The health state determining means can alsocomprise a chemical sensor for analyzing the amount of carbon dioxide inthe passenger compartment or around the at least one occupant or fordetecting the presence of blood in the passenger compartment. Movementof the occupant can be determined by monitoring the weight distributionof the occupant(s), or an analysis of waves from the space occupied bythe occupant(s). Each wave-receiving sensor generates a signalrepresentative of the waves received thereby and the generating meansmay comprise a processor for receiving and analyzing the signal from thewave-receiving sensor in order to generate the information about theoccupancy of the passenger compartment. The processor can comprisepattern recognition means for classifying an occupant of the seat sothat the information about the occupancy of the passenger compartmentincludes the classification of the occupant. The wave-receiving sensormay be a micropower impulse radar sensor adapted to detect motion of anoccupant whereby the motion of the occupant or absence of motion of theoccupant is indicative of whether the occupant is breathing. As such,the information about the occupancy of the passenger compartmentgenerated by the generating means is an indication of whether theoccupant is breathing. Also, the wave-receiving sensor may generate asignal representative of the waves received thereby and the generatingmeans receive this signal over time and determine whether any occupantsin the passenger compartment are moving. As such, the information aboutthe occupancy of the passenger compartment generated by the generatingmeans includes the number of moving and non-moving occupants in thepassenger compartment.

[0557] A related method for obtaining and conveying information aboutoccupancy of a passenger compartment of a vehicle comprises the steps ofreceiving waves from the passenger compartment, generating informationabout the occupancy of the passenger compartment based on the receivedwaves, and transmitting the information about the occupancy of thepassenger compartment whereby response personnel can receive theinformation about the occupancy of the passenger compartment. Waves maybe transmitted into the passenger compartment whereby the transmittedwaves are modified by passing into and at least partially through thepassenger compartment and then received. The information about theoccupancy of the passenger compartment may be stored in at least onememory unit which is subsequently interrogated upon a crash of thevehicle to thereby obtain the information about the occupancy of thepassenger compartment. A signal representative of the received waves canbe generated by sensors and analyzed in order to generate theinformation about the state of health of at least one occupant of thepassenger compartment and/or to generate the information about theoccupancy of the passenger compartment (i.e., determine non-reflexivemovement and/or breathing indicating life). Pattern recognitiontechniques, e.g., a trained neural network, can be applied to analyzethe signal and thereby recognize and identify any occupants of thepassenger compartment. In this case, the identification of the occupantsof the passenger compartment can be included into the information aboutthe occupancy of the passenger compartment.

[0558] All of the above-described methods and apparatus, as well asthose further described below, may be used in conjunction with oneanother and in combination with the methods and apparatus for optimizingthe driving conditions for the occupants of the vehicle describedherein.

[0559] Also described above is an embodiment of a component diagnosticsystem for diagnosing the component in accordance with the inventionwhich comprises a plurality of sensors not directly associated with thecomponent, i.e., independent therefrom, such that the component does notdirectly affect the sensors, each sensor detecting a signal containinginformation as to whether the component is operating normally orabnormally and outputting a corresponding electrical signal, processormeans coupled to the sensors for receiving and processing the electricalsignals and for determining if the component is operating abnormallybased on the electrical signals, and output means coupled to theprocessor means for affecting another system within the vehicle if thecomponent is operating abnormally. The processor means preferablycomprise pattern recognition means such as a trained pattern recognitionalgorithm, a neural network, modular neural networks, an ensemble ofneural networks, a cellular neural network, or a support vector machine.In some cases, fuzzy logic will be used which can be combined with aneural network to form a neural fuzzy algorithm. The another system maybe a display for indicating the abnormal state of operation of thecomponent arranged in a position in the vehicle to enable a driver ofthe vehicle to view the display and thus the indicated abnormaloperation of the component. At least one source of additionalinformation, e.g., the time and date, may be provided and input meanscoupled to the vehicle for inputting the additional information into theprocessor means. The another system may also be a warning deviceincluding transmission means for transmitting information related to thecomponent abnormal operating state to a site remote from the vehicle,e.g., a vehicle repair facility.

[0560] In another embodiment of the component diagnostic systemdiscussed above, at least one sensor detects a signal containinginformation as to whether the component is operating normally orabnormally and outputs a corresponding electrical signal. A processor orother computing device is coupled to the sensor(s) for receiving andprocessing the electrical signal(s) and for determining if the componentis operating abnormally based thereon. The processor preferablycomprises or embodies a pattern recognition algorithm for analyzing apattern within the signal detected by each sensor. An output device (ormultiple output devices) is coupled to the processor for affectinganother system within the vehicle if the component is operatingabnormally. The other system may be a display as mentioned above or awarning device.

[0561] A method for automatically monitoring one or more components of avehicle during operation of the vehicle on a roadway entails, asdiscussed above, the steps of monitoring operation of the component inorder to detect abnormal operation of the component, e.g., in one or theways described above, and if abnormal operation of the component isdetected, automatically directing the vehicle off of the restrictedroadway. For example, in order to automatically direct the vehicle offof the restricted roadway, a signal representative of the abnormaloperation of the component may be generated and directed to a guidancesystem of the vehicle that guides the movement of the vehicle. Possiblythe directing the vehicle off of the restricted roadway may entailapplying satellite positioning techniques or ground-based positioningtechniques to enable the current position of the vehicle to bedetermined and a location off of the restricted highway to be determinedand thus a path for the movement of the vehicle. Re-entry of the vehicleonto the restricted roadway may be prevented until the abnormaloperation of the component is satisfactorily addressed.

[0562] Although several preferred embodiments are illustrated anddescribed above, there are possible combinations using other signals andsensors for the components and different forms of the neural networkimplementation or different pattern recognition technologies thatperform the same functions which can be utilized in accordance with theinvention. Also, although the neural network and modular neural networkshave been described as an example of one means of pattern recognition,other pattern recognition means exist and still others are beingdeveloped which can be used to identify potential component failures bycomparing the operation of a component over time with patternscharacteristic of normal and abnormal component operation. In addition,with the pattern recognition system described above, the input data tothe system may be data which has been pre-processed rather than the rawsignal data either through a process called “feature extraction” or byvarious mathematical transformations. Also, any of the apparatus andmethods disclosed herein may be used for diagnosing the state ofoperation or a plurality of discrete components.

[0563] In other embodiments disclosed above, the state of the entirevehicle is diagnosed whereby two or more sensors, preferablyacceleration sensors and gyroscopes, detect the state of the vehicle andif the state is abnormal, output means are coupled to the processormeans for affecting another system in the vehicle. The another systemmay be the steering control system, the brake system, the accelerator orthe frontal or side occupant protection system. An exemplifying controlsystem for controlling a part of the vehicle in accordance with theinvention thus comprises a plurality of sensor systems mounted atdifferent locations on the vehicle, each sensor system providing ameasurement related to a state of the sensor system or a measurementrelated to a state of the mounting location, and a processor coupled tothe sensor systems and arranged to diagnose the state of the vehiclebased on the measurements of the sensor system, e.g., by the applicationof a pattern recognition technique. The processor controls the partbased at least in part on the diagnosed state of the vehicle. At leastone of the sensor systems may be a high dynamic range accelerometer or asensor selected from a group consisting of a single axis accelerationsensor, a double axis acceleration sensor, a triaxial accelerationsensor and a gyroscope, and may optionally include an RFID responseunit. The gyroscope may be a MEMS-IDT gyroscope including a surfaceacoustic wave resonator which applies standing waves on a piezoelectricsubstrate. If an RFID response unit is present, the control system wouldthen comprise an RFID interrogator device which causes the RFID responseunit(s) to transmit a signal representative of the measurement of thesensor system associated therewith to the processor.

[0564] The state of the vehicle diagnosed by the processor may be thevehicle's angular motion, angular acceleration and/or angular velocity.As such, the steering system, braking system or throttle system may becontrolled by the processor in order to maintain the stability of thevehicle. The processor can also be arranged to control an occupantrestraint or protection device in an attempt to minimize injury to anoccupant.

[0565] The state of the vehicle diagnosed by the processor may also be adetermination of a location of an impact between the vehicle and anotherobject. In this case, the processor can forecast the severity of theimpact using the force/crush properties of the vehicle at the impactlocation and control an occupant restraint or protection device based atleast in part on the severity of the impact.

[0566] The system can also include a weight sensing system coupled to aseat in the vehicle for sensing the weight of an occupying item of theseat. The weight sensing system is coupled to the processor whereby theprocessor controls deployment or actuation of the occupant restraint orprotection device based on the state of the vehicle and the weight ofthe occupying item of the seat sensed by the weight sensing system.

[0567] A display may be coupled to the processor for displaying anindication of the state of the vehicle as diagnosed by the processor. Awarning device may be coupled to the processor for relaying a warning toan occupant of the vehicle relating to the state of the vehicle asdiagnosed by the processor. Further, a transmission device may becoupled to the processor for transmitting a signal to a remote siterelating to the state of the vehicle as diagnosed by the processor.

[0568] The state of the vehicle diagnosed by the processor may includeangular acceleration of the vehicle whereby angular velocity and angularposition or orientation are derivable from the angular acceleration. Theprocessor can then be arranged to control the vehicle's navigationsystem based on the angular acceleration of the vehicle.

[0569] A method for controlling a part of the vehicle in accordance withthe invention comprises the step of mounting a plurality of sensorsystems at different locations on the vehicle, measuring a state of thesensor system or a state of the respective mounting location of thesensor system, diagnosing the state of the vehicle based on themeasurements of the state of the sensor systems or the state of themounting locations of the sensor systems, and controlling the part basedat least in part on the diagnosed state of the vehicle. The state of thesensor system may be any one or more of the acceleration, angularacceleration, angular velocity or angular orientation of the sensorsystem. Diagnosis of the state of the vehicle may entail determiningwhether the vehicle is stable or is about to rollover or skid and/ordetermining a location of an impact between the vehicle and anotherobject. Diagnosis of the state of the vehicle may also entaildetermining angular acceleration of the vehicle based on theacceleration measured by accelerometers if multiple accelerometers arepresent as the sensor systems.

[0570] Another control system for controlling a part of the vehicle inaccordance with the invention comprises a plurality of sensor systemsmounted on the vehicle, each providing a measurement of a state of thesensor system or a state of the mounting location of the sensor systemand generating a signal representative of the measurement, and a patternrecognition system for receiving the signals from the sensor systems anddiagnosing the state of the vehicle based on the measurements of thesensor systems. The pattern recognition system generates a controlsignal for controlling the part based at least in part on the diagnosedstate of the vehicle. The pattern recognition system may comprise one ormore neural networks. The features of the control system described abovemay also be incorporated into this control system to the extentfeasible.

[0571] The state of the vehicle diagnosed by the pattern recognitionsystem may include a state of an abnormally operating component wherebythe pattern recognition system is designed to identify a potentiallymalfunctioning component based on the state of the component measured bythe sensor systems and determine whether the identified component isoperating abnormally based on the state of the component measured by thesensor systems.

[0572] In one preferred embodiment, the pattern recognition system maycomprise a neural network system and the state of the vehicle diagnosedby the neural network system includes a state of an abnormally operatingcomponent. The neural network system includes a first neural network foridentifying a potentially malfunctioning component based on the state ofthe component measured by the sensor systems and a second neural networkfor determining whether the identified component is operating abnormallybased on the state of the component measured by the sensor systems.

[0573] Modular neural networks can also be used whereby the neuralnetwork system includes a first neural network arranged to identify apotentially malfunctioning component based on the state of the componentmeasured by the sensor systems and a plurality of additional neuralnetworks. Each of the additional neural networks is trained to determinewhether a specific component is operating abnormally so that themeasurements of the state of the component from the sensor systems-areinput into that one of the additional neural networks trained on acomponent which is substantially identical to the identified component.

[0574] Another method for controlling a part of the vehicle comprisesthe steps of mounting a plurality of sensor systems on the vehicle,measuring a state of the sensor system or a state of the respectivemounting location of the sensor system, generating signalsrepresentative of the measurements of the sensor systems, inputting thesignals into a pattern recognition system to obtain a diagnosis of thestate of the vehicle and controlling the part based at least in part onthe diagnosis of the state of the vehicle.

[0575] In one notable embodiment, a potentially malfunctioning componentis identified by the pattern recognition system based on the statesmeasured by the sensor systems and the pattern recognition systemdetermine whether the identified component is operating abnormally basedon the states measured by the sensor systems. If the pattern recognitionsystem comprises a neural network system, identification of thecomponent entails inputting the states measured by the sensor systemsinto a first neural network of the neural network system and thedetermination of whether the identified component is operatingabnormally entails inputting the states measured by the sensor systemsinto a second neural network of the neural network system. A modularneural network system can also be applied in which the states measuredby the sensor systems are input into a first neural network and aplurality of additional neural networks are provided, each being trainedto determine whether a specific component is operating abnormally,whereby the states measured by the sensor systems are input into thatone of the additional neural networks trained on a component which issubstantially identical to the identified component.

[0576] Another control system for controlling a part of the vehiclebased on occupancy of the seat in accordance with the inventioncomprises a plurality of strain gages mounted in connection with theseat, each measuring strain of a respective mounting location caused byoccupancy of the seat, and a processor coupled to the strain gages andarranged to determine the weight of an occupying item based on thestrain measurements from the strain gages over a period of time, i.e.,dynamic measurements. The processor controls the part based at least inpart on the determined weight of the occupying item of the seat. Theprocessor can also determine motion of the occupying item of the seatbased on the strain measurements from the strain gages over the periodof time. One or more accelerometers may be mounted on the vehicle formeasuring acceleration in which case, the processor may control the partbased at least in part on the determined weight of the occupying item ofthe seat and the acceleration measured by the accelerometer(s). Bycomparing the output of various sensors in the vehicle, it is possibleto determine activities that are affecting parts of the vehicle whilenot affecting other parts. For example, by monitoring the verticalaccelerations of various parts of the vehicle and comparing theseaccelerations with the output of strain gage load cells placed on theseat support structure, a characterization can be made of the occupancyof the seat. Not only can the weight of an object occupying the seat bedetermined, but also the gross motion of such an object can beascertained and thereby an assessment can be made as to whether theobject is a life form such as a human being. Strain gage weight sensorsare disclosed in U.S. patent application Ser. No. 09/193,209 filed Nov.17, 1998 (corresponding to International Publication No. WO 00/29257),which is incorporated herein by reference its entirety as if the entireapplication were set forth herein. In particular, the inventorscontemplate the combination of all of the ideas expressed in this patentapplication with those expressed in the current invention.

[0577] Although several preferred embodiments are illustrated anddescribed above, there are possible combinations using other geometries,sensors, materials and different dimensions for the components thatperform the same functions. This invention is not limited to the aboveembodiments and should be determined by the following claims.

I claim:
 1. A vehicle, comprising: a diagnostic system arranged todiagnose the state of the vehicle or the state of a component of thevehicle and generate an output indicative or representative thereof; anda communications device coupled to said diagnostic system and arrangedto transmit the output of said diagnostic system.
 2. The vehicle ofclaim 1, wherein said diagnostic system comprises a plurality of vehiclesensors mounted on the vehicle, each of said sensors providing ameasurement related to a state of said sensor or a measurement relatedto a state of the mounting location and a processor coupled to saidsensors and arranged to receive data from said sensors and process thedata to generate the output indicative or representative of the state ofthe vehicle or the state of a component of the vehicle.
 3. The vehicleof claim 2, wherein said sensors are wirelessly coupled to saidprocessor.
 4. The vehicle of claim 2, wherein said processor embodies apattern recognition algorithm trained to generate the output from thedata received from said sensors.
 5. The vehicle of claim 1, furthercomprising a display arranged in the vehicle in a position to be visiblefrom the passenger compartment, said display being coupled to saiddiagnostic system and arranged to display the diagnosis of the state ofthe vehicle or the state of a component of the vehicle.
 6. The vehicleof claim 1, wherein said communications device comprises a cellulartelephone system including an antenna.
 7. The vehicle of claim 1,further comprising an occupant sensing system arranged to determine atleast one property or characteristic of occupancy of the vehicle, saidcommunications device being coupled to said occupant sensing system andarranged to transmit the determined property or characteristic ofoccupancy of the vehicle.
 8. The vehicle of claim 1, further comprisingat least one environment sensor each sensing a state of the environmentaround the vehicle, said communications device being coupled to said atleast one environment sensor and being arranged to transmit the sensedstate of the environment around the vehicle.
 9. The vehicle of claim 1,further comprising a memory unit coupled to said diagnostic system andsaid communications device, said memory unit being arranged to receivethe diagnosis of the state of the vehicle or the state of a component ofthe vehicle from said diagnostic system and store the diagnosis, saidcommunications device being arranged to interrogate said memory unit toobtain the stored diagnosis to enable transmission thereof.
 10. Thevehicle of claim 1, wherein said diagnostic system comprises a pluralityof sensors mounted at different locations on the vehicle, each of saidsensors providing a measurement related to a state of said sensor or ameasurement related to a state of the mounting location and a processorcoupled to said sensor systems and arranged to diagnose the state of thevehicle or the state of the component of the vehicle based on themeasurements of said sensors.
 11. The vehicle of claim 10, wherein atleast one of said sensors is a sensor selected from a group consistingof a single axis acceleration sensor, a double axis acceleration sensor,a triaxial acceleration sensor and a gyroscope.
 12. The vehicle of claim10, wherein at least one of said sensors includes an RFID response unit,further comprising at least one RFID interrogator device, said at leastone interrogator device causing said RFID response units of said atleast one sensor to transmit a signal representative of the measurementof said at least one sensor to said processor.
 13. The vehicle of claim10, wherein at least one of said sensors includes a SAW sensor arrangedto receive a signal and return a signal modified by virtue of the stateof said SAW sensor or the state of the mounting location of said SAWsensor.
 14. The vehicle of claim 13, wherein said SAW sensor is arrangedto measure at least one of temperature and pressure.
 15. The vehicle ofclaim 13, wherein said SAW sensor is arranged to measure at least one ofthe presence and concentration of a chemical.
 16. The vehicle of claim1, wherein the state of the vehicle diagnosed by said diagnostic systemincludes angular motion of the vehicle.
 17. The vehicle of claim 1,wherein said processor is arranged to control at least one part of thevehicle based on the output indicative or representative of the state ofthe vehicle or the state of a component of the vehicle.
 18. The vehicleof claim 1, further comprising a warning device coupled to saiddiagnostic system for relaying a warning to an occupant of the vehiclerelating to the state of the vehicle or the state of the component ofthe vehicle as diagnosed by said diagnostic system.
 19. The vehicle ofclaim 1, further comprising a location determining system fordetermining the location of the vehicle, said communications devicebeing coupled to said location determining system and arranged totransmit the determined location of the vehicle.
 20. The vehicle ofclaim 19, wherein said location determining system uses GPS technology.21. A method for monitoring a vehicle, comprising the steps of:diagnosing the state of the vehicle or the state of a component of thevehicle by means of a diagnostic system arranged on the vehicle;generating an output indicative or representative of the diagnosed stateof the vehicle or the diagnosed state of the component of the vehicle;and transmitting the output to a remote location.
 22. The vehicle ofclaim 21, wherein the step of transmitting the output to a remotelocation comprises the step of arranging a communications devicecomprising a cellular telephone system including an antenna on thevehicle.
 23. The method of claim 21, wherein the state of the vehicle orthe state of the component of the vehicle is diagnosed by a processorembodying a pattern recognition algorithm.
 24. The method of claim 21,wherein the step of diagnosing the state of the vehicle comprises thestep of determining whether the vehicle is stable or is about torollover or skid.
 25. The method of claim 21, wherein the step ofdiagnosing the state of the vehicle comprises the step of determining alocation of an impact between the vehicle and another object.
 26. Themethod of claim 21, further comprising the steps of: arranging a displayin the vehicle in a position to be visible from the passengercompartment; and displaying the state of the vehicle or the state of acomponent of the vehicle on the display.
 27. The method of claim 21,further comprising the step of relaying a warning to an occupant of thevehicle relating to the state of the vehicle. 28 The method of claim 21,further comprising the steps of: determining at least one property orcharacteristic of occupancy of the vehicle; and transmitting thedetermined property or characteristic of occupancy of the vehicle to aremote location.
 29. The method of claim 28, wherein the step ofdetermining at least one property or characteristic of occupancy of thevehicle comprises the step of determining the number of occupants in thepassenger compartment.
 30. The method of claim 21, further comprisingthe steps of: sensing a state of the environment around the vehicle; andtransmitting information about the environment of the vehicle to aremote location.
 31. The method of claim 21, further comprising thesteps of: providing a memory unit in the vehicle to receive thediagnosis of the state of the vehicle or the state of the component ofthe vehicle and store the diagnosis; and interrogating the memory unitto obtain the stored diagnosis to enable transmission thereof.
 32. Themethod of claim 21, wherein the step of diagnosing the state of thevehicle or the state of the component of the vehicle comprises the stepsof mounting a plurality of sensors on the vehicle, measuring a state ofeach sensor or a state of the mounting location of each sensor anddiagnosing the state of the vehicle or the state of a component of thevehicle based on the measurements of the state of the sensors or thestate of the mounting locations of the sensors.
 33. The method of claim32, wherein the state of the vehicle or the state of the component ofthe vehicle is diagnosed by a processor, further comprising the step ofwirelessly coupling the sensors to the processor.
 34. The method ofclaim 21, wherein the state of the vehicle is diagnosed by a processor,further comprising the steps of: providing at least one of the sensorswith an RFID response unit; mounting at least one RFID interrogatordevice on the vehicle; and transmitting signals via the at least oneRFID interrogator device to cause the RFID response units of the atleast one sensor to transmit a signal representative of the measurementsof the at least one sensor to the processor.
 35. The method of claim 21,wherein the state of the vehicle is diagnosed by a processor, furthercomprising the step of providing at least one of the sensors as a SAWsensor capable of receiving a signal and returning a signal modified byvirtue of the state of the SAW sensor or the state of the mountinglocation of the SAW sensor.
 36. The method of claim 35, wherein the SAWsensor is arranged to measure at least one of temperature and pressure.37. The method of claim 35, wherein the SAW sensor is arranged tomeasure at least one of concentration and presence of a chemical. 38.The method of claim 21, wherein the step of transmitting the output to aremote location comprises the step of transmitting the output to asatellite for transmission from the satellite to the remote location.39. The method of claim 21, wherein the step of transmitting the outputto a remote location comprises the step of transmitting the output viathe Internet to a web site or host computer associated with the remotelocation.
 40. The method of claim 21, further comprising the steps of:determining the location of the vehicle; and transmitting the determinedlocation of the vehicle to the remote location in conjunction with theoutput.
 41. A vehicle, comprising: a diagnostic system arranged todiagnose the state of the vehicle or the state of a component of thevehicle and generate an output indicative or representative thereof; anda communications device coupled to said diagnostic system and arrangedto transmit the output of said diagnostic system, said communicationsdevice including a transmitter for transmitting a signal representativeof the output of said diagnostic system to a satellite for transmissionfrom the satellite to a remote site.
 42. The vehicle of claim 41,wherein said diagnostic system comprises a plurality of vehicle sensorsmounted on the vehicle, each of said sensors providing a measurementrelated to a state of said sensor or a measurement related to a state ofthe mounting location and a processor coupled to said sensors andarranged to receive data from said sensors and process the data togenerate the output indicative or representative of the state of thevehicle or the state of a component of the vehicle.
 43. The vehicle ofclaim 42, wherein said sensors are wirelessly coupled to said processor.44. The vehicle of claim 42, wherein said processor embodies a patternrecognition algorithm trained to generate the output from the datareceived from said sensors.
 45. The vehicle of claim 41, furthercomprising a display arranged in the vehicle in a position to be visiblefrom the passenger compartment, said display being coupled to saiddiagnostic system and arranged to display the diagnosis of the state ofthe vehicle or the state of a component of the vehicle.
 46. The vehicleof claim 41, further comprising an occupant sensing system arranged todetermine at least one property or characteristic of occupancy of thevehicle, said communications device being coupled to said occupantsensing system and arranged to transmit the determined property orcharacteristic of occupancy of the vehicle.
 47. The vehicle of claim 41,further comprising at least one environment sensor each sensing a stateof the environment around the vehicle, said communications device beingcoupled to said at least one environment sensor and being arranged totransmit the sensed state of the environment around the vehicle.
 48. Thevehicle of claim 41, further comprising a memory unit coupled to saiddiagnostic system and said communications device, said memory unit beingarranged to receive the diagnosis of the state of the vehicle or thestate of a component of the vehicle from said diagnostic system andstore the diagnosis, said communications device being arranged tointerrogate said memory unit to obtain the stored diagnosis to enabletransmission thereof.
 49. The vehicle of claim 41, wherein saiddiagnostic system comprises a plurality of sensors mounted at differentlocations on the vehicle, each of said sensors providing a measurementrelated to a state of said sensor or a measurement related to a state ofthe mounting location and a processor coupled to said sensor systems andarranged to diagnose the state of the vehicle or the state of thecomponent of the vehicle based on the measurements of said sensors. 50.The vehicle of claim 49, wherein at least one of said sensors is asensor selected from a group consisting of a single axis accelerationsensor, a double axis acceleration sensor, a triaxial accelerationsensor and a gyroscope.
 51. The vehicle of claim 49, wherein at leastone of said sensors includes an RFID response unit, further comprisingat least one RFID interrogator device, said at least one interrogatordevice causing said RFID response units of said at least one sensor totransmit a signal representative of the measurement of said at least onesensor to said processor.
 52. The vehicle of claim 49, wherein at leastone of said sensors includes a SAW sensor arranged to receive a signaland return a signal modified by virtue of the state of said SAW sensoror the state of the mounting location of said SAW sensor.
 53. Thevehicle of claim 41, wherein the state of the vehicle diagnosed by saiddiagnostic system includes angular motion of the vehicle.
 54. Thevehicle of claim 41, wherein said processor is arranged to control atleast one part of the vehicle based on the output indicative orrepresentative of the state of the vehicle or the state of a componentof the vehicle.
 55. The vehicle of claim 41, further comprising awarning device coupled to said diagnostic system for relaying a warningto an occupant of the vehicle relating to the state of the vehicle orthe state of the component of the vehicle as diagnosed by saiddiagnostic system.
 56. The vehicle of claim 41, further comprising alocation determining system for determining the location of the vehicle,said communications device being coupled to said location determiningsystem and arranged to transmit the determined location of the vehicle.